Archive of Our Own

It had become sort of a habit for the two Slayers.

Whenever Inosuke was curious about something and Tanjirō wasn’t around to explain it to him, Shinobu would be the one he would reach to for answers.

He wouldn’t say it out loud to her, but every time she was able to figure out what he was asking even though he was rather awful at explaining himself and give him a satisfactory answer, he couldn’t help but admire her a bit more.

Over time, it wouldn’t be unusual to see the boy following her around the Butterfly Estate like a puppy to its dam, or waiting outside the door to her office if he had already been kicked off from it by the woman herself. The Insect Hashira had even caught the boy’s friends joking about him seeing her as his mother, to which she had answered that she wasn’t old enough for that, making the two younger Slayers apologize terrified of her fake smile as she scolded them.

However, Shinobu couldn’t say she minded the teen’s attention. Her own little sister was a rather reserved and polite girl, so it was something new for her as well.

Besides, the way his beautiful eyes would shine as he enthusiastically listened to her speech made him look even cuter. She’d ask him to take off his beloved mask specifically so she would be able to see his adorable expressions, and if he was in a particularly good mood he would oblige. His strands of smooth-looking dark hair would fall rather unceremoniously to his face when he did, so she would have to reach for his face and discover the green-colored irises herself if she wanted to see them, as well as the pink on his cheeks that wouldn’t go unnoticed against the pure whiteness of his skin.

Since they had become so close, it was only natural for Inosuke to ask her of all people things like why his friend Tanjirō always became so excited whenever he would see the Water Hashira, or why Zenitsu insisted so much on marrying Nezuko or why he would spend so much time talking about how perfect girls were.

Shinobu couldn’t help chuckling when Inosuke told her that, in fact, he had tried to ask the boys directly about his doubts. But Tanjirō would only get as red as his hair and become apparently unable to talk without shuttering, meanwhile Zenitsu would laugh at his face and call him an idiot, not telling him what he wanted to know even after Inosuke had spent the whole evening chasing the poor blond around the garden to get him to either apologize or give him an answer.

Of course, Inosuke had got mad with her as well and put on his boar mask again despite her apologizing with the joyful expression still attached to her face.

Even though she did think that ignorance also made him cute, she also felt some sort of commitment as a doctor to explain to the teen what puberty was and how it was affecting his friends.

What she absolutely wasn’t expecting was for Inosuke to actually ask her to watch him jerk off and give him advice. And what was even more unexpected was that she had agreed to it.

“S-Shinobu…is this alright?”

“Hmmm. No, you’re gripping it too tightly. Be gentler”.

The boy gulped and the Hashira was able to hear the warm air escaping his mouth through the narrow aperture on his clenched teeth as he sighed. He had also shut his eyes tightly while trying to apply less strength on his half-hard erection.

He seemed like a totally different person from the wild boy who always faced anything he deemed a worthy enough challenge. This passiveness was so unlike him, but then again Shinobu couldn’t really blame him for feeling so nervous.

Even if he trusted her as mother figure, Shinobu guessed that exposing himself like this, his pants long forgotten on the floor as he sat cross-legged with one of his hands on his crotch, all while the other gripped the mattress over the bed which him and the Insect Hashira mere centimeters away from him were occupying, would be too much even for someone like him.

Her eyes the color of glycine watched focused how the boy’s calloused hand (bigger and rougher than hers, despite its owner being so young) gripped the base of his cock as he licked his lips and experimentally gave it a stroke. She heard him grunting almost pained and even while seeming collected, she suddenly felt her throat dry.  

Despite him trying his best to follow the woman’s advice, his strokes were still rather clumsy and violent. So much so that Shinobu could tell that the experience wasn’t as pleasurable to the boy as it would usually be. She sort of felt sorry for him, but the sight of such a beautiful young man struggling to keep himself together as he tried to pleasure his sensitive skin was something so delightful she couldn’t find it on herself to stop him.

Inosuke gave his cock a particularly strong stroke and he gasped definitely in pain before he obstinately kept trying to make his attempts to pleasure himself work, too prideful to let the woman he could feel staring at him in amusement hear him cry for her help.

“Oh my. You’re quite a spectacle, aren’t you?” the movements of his wrist suddenly stopped when he opened his eyes and found the woman so close to him he could even feel her warm breath against his cheek. “But you know, Inosuke-kun…I’m a bit worried. Just now you seemed to be really in pain, so maybe you could use a hand after all”.

“…I-It’s not necessary. I can do it myself”.

He hated how unbelieving the Hashira’s eyes felt on his skin. It was a gentle and understanding gaze like she was worried about his wellbeing as she affirmed to be, yet it also felt heavy and cold like iron to his senses. So overwhelming it made him wish to just give up and beg her to touch him, to praise him with that honey-dripping voice of hers.

“Is that so? It’s a shame”. He didn’t need to know her as much as he did to be able to tell that she didn’t find it regrettable at all. Perhaps he had just chosen the hardest path for himself by refusing to give in, because he could tell that she was actually enjoying his struggle. Like he was a plaything for her amusement.

He hated how aroused that thought made him feel too.

“Why did you stop, then? Keep going, please. I’ll just watch, as you asked”. Her slender fingers ghosted over the skin of the wrist he had just been using to jerk himself off as she talked. A gentle touch like the one from the wings of a butterfly that had him trembling under it in no time.

He didn’t close his eyes this time. Even if he still had his strong sense of touch, he felt more vulnerable to her if he wasn’t able to watch her movements.

His fingers closed around his cock again, gentler than before. It was visibly harder despite the fact that he hadn’t touched it in minutes – and even if he wasn’t the brightest guy he could tell it was because of Shinobu’s proximity to his almost naked body.

Of course, he knew she was aware as well.

“Your face is all red, Inosuke-kun. You look very pretty like this”.

The boy gasped when he felt her tongue licking the commissure of his lips. Apparently, he had bitten them so hard before he had made them bleed, but hadn’t been able to realize because of how focused he was on the woman in front of him.

The woman who was now grapping her soft fingers around his wrist. Not strong enough to stop his movements, but still slowly driving the sensitive young man insane.

“Are you sure you don’t want me to help you?” the words were whispered to his ear and a chill ran down his spine when he felt the Hashira’s warm breathing against it.

“I…I’m not pretty. Don’t call me that”.

Thanks to her proximity, he was also able to feel her soft laugh when he talked back. Her fingers loosened their already faint grip around his wrist and started running up and down his forearm, caressing the soft skin with its tips.

“Oh? You think so?” The woman stuck her tongue out and slowly licked the sweat off the side of Inosuke’s neck, who couldn’t stop a low whine to escape his lips. “But you’re really pretty, you know?”

Inosuke jerked back a bit when she got even closer – and he realized her action almost looked like a hug. She was resting her head against his chest as a palm of the hand that just now had been caressing his forearm was pressed over his abs. Shinobu was putting her weight on her other hand, which was now firmly planted between his thighs and just under the already painfully hard erection that begged for her attention.

Still unsure of how to respond, he remembered what he had learnt about physical affection and hugging from his friends, so he let one of his arms hold Shinobu closer to his chest, embracing her by her waist.

“Let’s see…you’ve always looked unbelievably beautiful to me. But this new side of you…feeling so disoriented and overwhelmed by this unknown, pleasant feeling. With your face such a deep red and your beautiful eyes so glazed from holding back tears – it almost makes me want to devour you”.

Every sweet word that came out of Shinobu’s mouth made the poor boy’s face grow redder and redder. The sensual tone she was using as she whispered them, like it was a precious secret she had carefully kept from everyone else but now was being entrusted to him, only made the whole situation feel even more embarrassing to him.

He leaned his head forward and hid it on the woman’s shoulder. She was still fully clothed, having undone only a few of the buttons of her uniform. Inosuke envied her for seeming so collected despite the fact that he could tell from her gaze earlier that she was lusting after him as well.

“I’m sure I’m not the only one who thinks like that, though. Any person – man or woman, would love to see you like this. Perhaps even your friends, do you really think they’ve never thought about you in that way?”

“S-Shinobu. Shinobu, please…”

“What do you think they would feel if they saw you right now? …Or even better, how would you feel if they did? How much would it take for you to break down and shamelessly beg them to touch you?”

“Shinobu, please…I need-”

His begging was stopped by a moan when the woman’s slender fingers moved up his torso and reached his pectoral, wasting no time in pinching the pink nipple when they did.

“Yes, what is it? If there’s something you want, feel free to tell me”.

“I need…please, Shinobu. Help me come”.

The boy was quickly rewarded by the hand travelling back to his crotch and immediately gripping the red head of his hard cock. He moaned again, higher than before as he embraced her with both arms, hiding his nose on her neck and feeling the woman’s floral smell enter his nose when he did. His fingers dug hard on the thick fabric of the uniform she wore.

Inosuke moved his hips forward and felt himself melt under Shinobu’s gentle touch as the hand wandered from his head to the base. Maybe it was because of her unique fighting style, but it was nowhere as rough as his own. Even though he could feel a few callouses caressing his length, the skin was still so soft he couldn’t handle how good it was making him feel.

“See? It’s nice to be helped, isn’t it?”

He knew she was totally mocking him, but right now, with his cock buried deeply on her firm grip as he snapped his hips again and again to feel more of the hand that was rather still in comparison, he couldn’t care less about how pathetic he looked or how much seeing him in this state amused her.

In fact, he wanted more of it. He wanted to hear her soft laugh as he eagerly thrust in her hand and wanted her to praise him more. It was so overwhelming he felt dizzy, and yet he couldn’t get enough of it.

“You love being rewarded like this, don’t you? You’re such a good boy, Inosuke”.

When the gentle words were whispered so close to his ear and with one last stroke from Shinobu, he bit on the fabric on her shoulder and thrust forward hard, burying himself as deep inside the soft hand as possible while coming.

Shinobu let him steady his breathing against her shoulder before she pulled him away from her. Inosuke looked rather curiously at the saliva string that extended from his parted lips to the part of her uniform he had bitten onto. He still felt disoriented from what Shinobu assumed to be his first orgasm.

The boy only looked up to her face when she cleared her throat to draw his attention back to her.  

She was showing him her hand, the one that wasn’t squeezing his shoulder. It didn’t took long for Inosuke to realize that it was covered in his own load, some of it even dripping dangerously close to the sleeve of her uniform.

“Look, you made a mess. What will you do about it?”

Inosuke only blinked a couple of times while staring at the stained hand before he sighed and stuck his tongue out, giving it a lick.

Taken off guard, Shinobu tried to retreat her hand and tell him not to do it, but the words died on her throat as he held her wrist with both hands and licked again.

When she gave up and decided to let him do as he wished, he started to lick more enthusiastically, even engulfing some of her fingers whole until all the semen on them had been replaced by his saliva. She was quite surprised that he didn’t seem disgusted at all by what he was doing, but the sight of him acting so willing to place her and clean his own seed off her hand was also very arousing in a different way than watching him try to jerk off had been.

He tuck his hair behind his ear before giving the palm a final lick and planted a kiss on it, staring at Shinobu right in the eyes as he did.

“I want to see you do it now”.

“What do you mean?” she did have an idea of what he wanted her to do, but she still wanted to hear it out of his own mouth.

“What I did before. Shinobu, you watched me touch myself, so I want to watch you too”.

“Eh~? When did you become so cocky to think you could negotiate with me?”

Inosuke looked down embarrassed when she answered. In fact, she had been feeling very aroused for a while and was planning to take care of herself whether the boy was in the room or not, but she couldn’t help teasing him a bit more before giving him what he wanted.

“…Please? I-I really want to watch you”.

“Well~ Since you’re asking so nicely, I’ll let you watch. But be grateful and make sure not to miss a detail, alright?”

“Okay! Thank you, Shinobu!”

He was nodding so full of enthusiasm that the Hashira could only compare him to a kid who had just been given a treat. The thought of having such an innocent boy watch her masturbate was arousing her even more than she already was. There were just too many things about Inosuke to mark, to wreck, and yet the boy was completely oblivious of such appeal.

She felt lucky she happened to be the first one to take advantage of that innocence.

Shinobu got up from the bed for a moment so she could take her clothes off. Her dear older sister’s haori had been neatly placed on a chair in front of it just after she had closed the door so Inosuke and her could have some very needed privacy, therefore she started undressing by the lower part of the uniform, undoing the belt and letting the smooth fabric fall down her legs until it hit the floor with a low sound.

She thought about it for a bit and decided to just undo the remaining buttons on the upper part but still keep the shirt and coat over her shoulders. At least for now.

The sight she found when she turned around and started to climb to the bed again was just what she was expecting – Inosuke was looking at her from head to toe, but specially focusing on her now exposed crotch. The Hashira could almost see the sparks on his eyes, and as she lowered her gaze she was also able to see how the boy’s cock started to harden again.

Inosuke kneeled over the mattress in a position that almost looked out of place in the usually impolite boy as Shinobu placed herself in front of him, resting her back on the bed and her head on the pillow.

The woman spread her legs slowly – making sure that Inosuke could watch every detail as he had promised to do. She could also see him from this angle, so she delighted on how the expression on his face was still timid but a bit hungrier than before, with his fists clenched over his knees as he gulped like his throat had just gone dry at the sight of her body.

Shinobu let the hand that still had some of Inosuke’s saliva on it run down her torso. She caressed the skin of her abdomen playfully, trying to make the boy in front of her as eager as possible before she kept going down.

Never keeping her gaze away from Inosuke’s shaking figure, she let out a low moan when she rubbed her clit with her thumb, realizing how swollen it was from her so-called foster son’s earlier display. She directed a lascivious smile towards him as she kept circling her thumb over the nub and marveled at how he licked his lips when their gazes met.

She wasted no time in guiding her index finger towards her entrance and pushing it inside, her inner walls naturally stretch but as wet as she had expected them to be. As she kept thrusting in and out herself, Shinobu let her free hand caress one of her breasts a bit, massaging it and pressing the hardening nipple while still focusing mostly on moving the finger inside her and the thumb over the most sensitive zone on her body.

“Oh!” The Hashira exclaimed when she moved the finger upwards at the same time she pressed her clit. She allowed herself to close her eyes and therefore didn’t see how Inosuke’s pupils dilated.

Shinobu had already added a second finger, scissoring them both against her passages and stretching the tight insides when the boy got closer to her spread legs.

He had gotten on all fours and was facing her cunt. Shinobu could feel his raged, hot breath against her and it gave her chills. For a moment she even wondered if he was planning to eat her out, but after she kept thrusting her fingers and he only watched attentively while humping against the mattress, she realized that he was only trying to get a better sight of her pleasuring herself.

Shinobu lowered her gaze and took a look at Inosuke’s aching cock. It was pressed against his stomach and hard, so much so that the poor boy had to fully arch his back to get some kind of pleasure from the clumsy bucking of his hips. He sounded so turned on and so, so frustrated. 

The older couldn’t help pitying him a bit.

“Inosuke-kun”. His name was a pleasure to pronounce while masturbating. Maybe she should try doing it when she was alone as well. “If you really want to, you can stick it inside”.

“What…what do you mean?” he looked at her in the eye as he answered and she could only imagine how foggy the horny teenager’s vision had to be.

Shinobu removed her own fingers from inside her and replaced them so that she was opening her folds with them. Her young lover got even closer and made a throaty sound that reminded her of a beast that was being prevented from devouring a pray in front of it. She delighted and let out a pleasured sigh when the hot breath hit her insides.

“You know exactly what I mean. I explained to you the theory not long ago, didn’t I?”

“Y-yes, you did. I’m sorry”.

“Then…what are you waiting for?”

The wild boy snapped back to reality when he heard her last statement. Still shaking and unsure of what to do, he placed a hand over her soft thigh and squeezed it a bit.

When he got a positive reaction from her, he gripped his other hand around his erection and guided it towards the pink aperture that he tried his best not to imagine how good would feel for the sake of lasting enough to be able to pleasure his mother figure.

“…’Nobu- ah!” Inosuke wasn’t even able to speak properly when his head entered the tight entrance. He shut his eyes tightly and let out a deep moan when the wet, warm insides pressed against his sensitive skin like they were trying to suck him in.

“Hah…Inosuke, you have to go slowly at first. Take your time to fit it in”.

The younger slayer nodded at the woman’s words and he clenched his teeth. He could faintly taste something metallic, so he guessed he had bitten himself again. The pain itself felt like sometime so foreign and remote when his strong sense of touch was being overwhelmed by the most intense pleasure he had ever felt.

Still squeezing the milky-white thigh (which looked so much prettier when it was starting to redden by the manhandling, Inosuke realized) with his other hand, Inosuke removed the one that had been gripping his cock from it and placed it on Shinobu’s hip instead, pressing the bone with his thumb while the fingers dug on the skin of her side.

Inosuke was obviously inexperienced, and far from the best encounter Shinobu had had – but the sight of the usually brave and cocky boy with his delicate, almost feminine features blushed to a deep-crimson color. With his long eyelashes hiding the beautiful green eyes from her as he remained unable to keep them open while gasping for air, like he had even forgotten how to breathe – to Shinobu, all of it made up for the lack of experience.

In fact, being with him like this was sort of a big turn on by itself. She could imagine how they both looked, his big and muscular body completely covering her smaller one. His rough, calloused hand desperately holding onto the smooth skin of her thigh as he sobbed from the visceral feeling, like he was trying to grab onto something to keep himself sane.

Oh, how she wished to ride him until he would be nothing but a sobbing, moaning mess who could remember nothing but her own name as he begged her for more.

The thought itself almost made her lose control and give in to her desires, but she remembered that she was supposed to be teaching him – and that it was his first time after all. It would be a shame to break him like that so soon.

Instead, she extended her arms towards him and held him by his hips, conducing him a bit more inside of her and gaining a surprised moan when she did. When he looked at her in the eye again, she smiled as reassuringly as she could, and despite how disoriented and unsure the boy still looked, he gave another small nod before he kept advancing through her passage.

“Hah…Good boy, Inosuke. You’re doing so great”.

Shinobu complimented him when the boy fully sheathed his length inside her, knowing those were the right buttons to press on him in a situation like this and also because she could tell he was doing his best despite his inexperience.

So she wanted him to feel good – as a reward, perhaps.

Inosuke had now both of his hands attached to her hips. His body was curved over hers and his strands of smooth hair fell over her breasts, making her feel tickles. She could also hear his raged breath, restless as the boy tried to drown his own moans before they could come out of his parted pink lips, which were wet with the saliva that was falling down the commissure of his mouth.

When what seemed to be a couple of minutes passed and he still hadn’t moved, she was considering taking the lead again and move her hips to encourage the boy to keep going, but it wasn’t necessary.

Shinobu could still feel his hands shaking against her hips as he jerked back a bit, just a few inches, before slamming himself all inside her in an abrupt movement.

They both moaned deeply at Inosuke’s first thrust. The older of the two still having yet to feel completely good, but positively delighted at the young man’s enthusiasm even if he was being rather brusque to her.

It couldn’t be helped. No matter how much she had tamed him, Inosuke was still a wild beast that would quickly lose control if he was left to do as he wished.

How she loved that part of him as well.

“Shinobu- Shinobu, you feel so good. I-I can’t stop now.” The boy talked slowly between each of his raged breaths. Shinobu only laughed before she answered him.

“Then don’t stop. Keep filling me to your heart’s content”.

The woman locked her slender legs around his hips, keeping him as close to her as possible while making sure he wouldn’t be able to back up. She rested her feet against the muscular lower back and let her warm hands ghost over the hard biceps before slamming her own hips against his, driving him as deep as he could reach.

“Shit! Ah- Shinobu!”

His fingers dug deeper on her sides as he started thrusting in and out of her all by himself, still clenching his teeth as he felt the melting pleasure of her insides grapping themselves around her. He truly had never felt something so good, Shinobu’s hand – let alone his own, were nowhere close to this feeling.

Why hadn’t he tried it before? Had his underlings already done this kind of thing with other people and kept such an amazing treasure hidden from him? Hell, maybe he could have even done it with them – though he should still ask Shinobu for advice before it.

Shinobu. Shinobu was the only one who he could have first experienced this with. It wouldn’t felt right if it was with someone else – Monitsu and Kentarō had called her something like “his foster mother” before, right? Yeah, it wouldn’t be okay for him to betray his own mother like that. He had to be a good child for her.

He had to make her feel good as well.

As he kept sheathing his cock inside her and marveled at the tightness of her entrance, he remembered what Shinobu was doing earlier and brought one of his hands to the aching nub over her hole, brusquely pressing his thumb against it as he thrust.

“Ah! Inosuke!”

Shinobu arched her back at Inosuke’s sudden attack. The nerves inside her had also started to make her feel good when the wild boy hit her inner walls mercilessly, so him adding an external stimulation was giving her a pleasure cruder and more straightforward than the one she got from watching him desperately buckling his hips alone.

Inosuke mounted her like she had expected – like a beast with the sole purpose of getting more and more of the addictive feeling that was completely foreign to it. Once she had given him her permission, he had started to thrust into her fast and without an apex of control or reasoning at all, as if the feeling was so overwhelming he had become unable to think.

Her body was intoxicating him, he felt like he could get addicted to the feeling of it if he wasn’t careful. But he didn’t want to be careful, he wanted to give in and entrust himself to her, to be held against her bosom until the end of the world.

It felt good. It felt safe. That was all that mattered.

“M-Mother…”

Shinobu’s eyes snapped back open when she heard his cry of pleasure. It had taken her off guard, but it wouldn’t be fair of her to blame him for it or scold him when he was in such a vulnerable position.

After all, she knew how he felt about her from the beginning. She would be lying if she said that wasn’t part of what made it so much arousing that anything she had experienced before.

“That’s right. Be a good boy and come for your mother”.

The words were spoken with a soft, tender feeling that to them. Such as only Shinobu was able to. And they made him feel a warmth inside him that had nothing to do with the mind-blowing pleasure.

He held her hips violently and buried his whole length inside her one last time, growling as he started emptying himself inside of her. Her tight walls squeezing him through the entirety of his second orgasm and making his over-sensitive body feel like it had just reached heaven.

As Inosuke kept filling her with the warm load, Shinobu let her hips snap against him a couple more of times as her hand reached her clit again and rubbed it, driving a lighting-like strike through her spine before she came with a loud moan that she wished the walls of the room would be able to stop from reaching any of the occupied ones on the sick bay.

When she came back to her senses, she realized Inosuke was still inside of her – but seemed to be as drain of energy as she was. He was nibbling on her neck like a puppy too sleepy to play and even if she wasn’t still under the effects of her orgasm she would have found him adorable.

But there was a problem.

“Ouch! Shinobu, that hurts!”

“You should have thought about that sooner. Didn’t you pay any attention when I was teaching you the theory?”

“What are you talking about?” Since she was pinching his nose with her fingers, his voice came out rather nasal. She couldn’t take him seriously even if he sounded so annoyed at her.

“I thought I told you that it’s important not to come inside. I’m a doctor, so I have methods, but that doesn’t mean you can be so careless”.

Now he was looking at her like a puppy that was being scolded, but Shinobu knew better than to fall for such a trick. Especially if it was Inosuke of all people. He had chosen her as his guardian, so she couldn’t just let him do as he wished and go unpunished.

“I’m sorry. But…” he met her gaze for the first time since she started to reprimand him. His hair was wet from the sweat and attached to his forehead, but she guessed that had nothing to do with his face growing all red again. “If I promise you not to come inside, can we do this again?”

After all, she couldn’t truly get mad at him.

“Alright. But only if you beat Kanao-chan at least once in this week’s training”.

“That’s not fair! That woman’s a total monster, even Gonpachiro has a hard time beating her!”

“Then that means you’ll have to do your best, right?”

Inosuke sighed in defeat and Shinobu knew he had accepted the challenge, even if reluctantly.

She extended her arms towards him and locked them around his neck. She saw the surprise and question on his beautiful eyes before she closed hers and pressed her lips against the boy’s.

They tasted like spit and sweat and even had a faint taste of blood on them – but she didn’t mind it at all as she bit his bottom lip and let her tongue enter his mouth when he opened it to let out a surprised noise. She barely had a taste of his wet tongue before she pulled away from him.

“You get that in advance. I’ll be looking forward to next weekend, Inosuke-kun~”

The boy looked like she had just swallowed the words out of him. His lips were slightly parted and his sight stayed fixated on her face before he understood the meaning of her words and his eyes burnt with motivation.

“Of course I’ll beat that Kanoko girl! I’m the King of the Mountain, after all. Shinobu can leave everything to me!”

He sounded so full of himself despite the fact that he had been acting all shy and clingy to her just a moment ago that even though she knew he was being absolutely serious she still could only find him cute.

But she was being serious about hoping for him to win as well.

After all, she had found such a rare, precious jewel all by herself. It would be a shame not to take full advantage of it.