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In their third year of high school, Katsuki and Izuku finally get together. Finally because for pretty much everyone else, it felt like they had been dancing around one another for fucking ever. If they didn’t start dating by their third year of high school, they probably would have killed each other. That kind of electricity only leads to sparks or a blackout, and luckily for everyone involved, the sparks didn’t fly out of control or take down anyone in their wake.
At least, that’s what Katsuki thought at first.
In hindsight, maybe it should have been more obvious. It’s not like it was just some sudden change that happened over night — the behavior started way before that. It was a gradual thing that snowballed into an avalanche and Katsuki feels like an idiot for not realizing it sooner.
It started with a few off-hand comments muttered under Izuku’s breath that were easy enough to ignore. It’s just that Katsuki never thought of Izuku as that kind of person before, so he didn’t read too much into it. This was Kaminari they were talking about, after all, so Katsuki didn’t even want to go there.
Tonight, though, Katsuki can’t ignore it any longer. They’re at Class B’s annual summer party and the energy is high. Since it’s their last year, everyone is emotional and drinking too much and partying too hard. Once they graduate in March, everything is going to change for them. No more study sessions or staying up too late trying to cram for a test. No more simulations or work studies or dorm room parties that will inevitably get broken up by Aizawa once one of them starts puking from drinking too much.
After this, it’s all real life and fighting villains and professional hero work. Some of them probably won’t make it in the industry and the ones who do might not make it to their twenty-first birthday, and that’s terrifying. So they go all out. They listen to loud music and dance a little closer than usual and they drink it all in — they savor these moments, treasure them because if anyone knows the value of their own lives it's their graduating class.
Which is why Katsuki cannot fucking phathom any reason why Izuku is standing in the corner of the room holding a red solo cup and glaring at Denki Kaminari. He looks miserable, a sour expression on his face that Katsuki does not recognize. It’s been a few months of this behavior and it’s only gotten worse as time goes by. Katsuki doesn’t really understand it because in the time he’s known Izuku (which is pretty much their entire lives), he’s never known Izuku to be angry at anyone, let alone hold some kind of petty grudge.
Maybe something happened between them that Katsuki doesn’t know about? Katsuki doubts it, though, since Izuku and Ochako dated during their first year and they’re still friends in spite of their break up. Izuku Midoriya is literally the most forgiving person Katsuki knows — to a fucking fault, most of the time. Everything is always sunshine and fucking rainbows when it comes to Izuku, so Katsuki genuinely has no idea what his boyfriend’s problem is with their classmate.
Annoyed and unable to take it anymore, Katsuki downs the rest of his beer and stomps across the room to Izuku.
“Oi, what’s wrong with you?” Katsuki asks, always preferring to be blunt over passive aggression.
Izuku startles, his gaze too focused on staring daggers into Denki Kaminari’s back to notice that Katsuki was even walking over to him. His face softens when he sees Katsuki, the lines between his eyebrows smooth out and he smiles, all warm and bright.
“Kacchan,” Izuku says softly. He turns his whole body, melts into the space between them like it’s just second nature for him. “I was wondering where you were.”
Katsuki can’t help the rush of heat that makes his cheeks burn. The alcohol isn’t helping.
Izuku looks good. He’s wearing a tight-fitting black tee shirt and a turquoise flannel with the sleeves rolled up to his elbows. He hit a growth spurt during Christmas break last year and came back to school with fucking chin stubble and Katsuki still isn’t over it. He’s taller than Katsuki now, too, which is weird but also nice. The way he turns and faces Katsuki — the way he cages him in with his arms, makes Katsuki feel safe and warm.
“I’ve been here the whole time, idiot,” Katsuki says, swallowing past the lump in his throat. The beer is making his head fuzzy and Izuku looks so hot like this, and Katsuki kind of wants to forget about the whole fucking thing and just sneak back to his dorm room and—
The thought is pulled from his mind when someone comes out of nowhere and practically knocks Katsuki into a wall with a hug.
“Kacchan~” Kaminari says, nuzzling his face into Katsuki’s neck.
Katsuki stiffens and shoves his classmate away, shooting him a dirty look. Kaminari couldn’t have picked a worse time to show up. Katsuki glances up at Izuku and finds that his gentle expression is gone. He’s not looking at Katsuki anymore. He’s not even looking at Kaminari — he’s staring down into his drink and swirling the contents a little too pointedly to be deliberate. Those awful lines are back between his brows and he’s frowning, Katsuki wants to reach out and smooth the lines away with his thumbs. He wants to kiss the frown off of his face.
“Get the fuck off of me,” Katsuki snaps, holding his arms out to keep Kaminari away.
Kaminari pouts. “Aww, come on Kacchan,” he drawls, speech slurred from too much drinking. “Come dance with me, I love this song.”
Katsuki rolls his eyes. “Dude, you fucking reek. How much have you had to drink?”
Kaminari grabs his chin thoughtfully and hums loudly. “Seven?”
Katsuki blinks. “Seven, what? Seven drinks?”
“Wait, no,” Kaminari says. “Eight? I think it was eight. Aaaand I had one of Sero’s gummies.”
Great. So Kaminari is fucking shit-faced and he’s trying to make it Katsuki’s problem. Maybe this is Izuku’s problem with him? He tends to get pretty fucked up at most parties on campus, so maybe Izuku is just tired of having to play babysitter.
“Why are you bothering me ?” Katsuki asks, glaring. “Isn’t your boyfriend here?”
Kaminari’s expression falters for a moment, but he recovers. “Who? Hitoshi? He’s not — we’re just friends , Kacchan, duh.”
“Weren’t you making out with him like, half an hour ago?” Katsuki knows for certain that he was indeed sucking face with their blue-haired classmate. He had unfortunately needed to pee in the same bathroom where they decided to make a whole god damn show out of practically fucking on the shared sinks. They didn’t even acknowledge that he walked in and didn’t stop even when Katsuki had to reach underneath them to get soap from the dispenser.
Kaminari wrinkles his nose. “He’s bullshit,” he slurs, rocking on his feet. “He doesn’t know anything because he’s bullshit.”
“Right,” Katsuki says. “Well you can fuck off now, because I want a turn making out with my boyfriend.”
Kaminari’s face lights up, like he just realized that Izuku is standing there with them.
“Deku~” he says, smiling brightly. “You look nice, have you been working out?”
Izuku bites his bottom lip and doesn’t quite meet Kaminari’s eyes when he says, “Hello, Kaminari.”
“Aww, come on. You know you can call me Denki. We’re friends, aren’t we?” Kaminari is barely standing now, so Katsuki reaches out to catch him before the asshole falls on his ass. When he wraps his arms around Kaminari, Izuku’s glare deepens.
And that’s when it hits him.
Izuku is jealous of Kaminari.
The realization is almost enough to knock Katsuki on his own ass. Izuku Midoriya? Mr. “I’m friends with everyone” and “friendship is power” is jealous of Denki fucking Kaminari? Katsuki would laugh if the situation weren’t so serious. Izuku holds his drink a little tighter and physically recoils in on himself at Katsuki’s contact with Kaminari.
“Fucking shit, dude, you need to go to bed,” Katsuki growls, steadying Kaminari where he stands. He looks around the room for someone to help him and he spots Ashido sharing a joint with Sero.
Katsuki starts to try to get her attention, when Shinso shows up out of fucking nowhere.
“Denki,” Shinso says, as if Katsuki isn’t the person holding Kaminari up so he doesn’t collapse on the floor. “You need to drink some water.”
Kaminari glares at him. Or, well, Katsuki thinks it’s supposed to be a glare? He narrows his eyes into slits and purses his lips, leaning in close to Shinso’s face.
“Don’t ‘el me whadda do,” Kaminari says, pointing a finger in the wrong direction. “You left me all alone.”
Shinso sighs and pinches the bridge of his nose. “Denki, I went to get you a water bottle. I told you where I was going.”
Kaminari freezes and then makes that dumb face he makes when he’s trying to remember something.
“I don’t believe you,” he says. Katsuki wants to punch both of them.
Shinso holds up a bottle of water, still cold from the vending machine. “Why would I lie to you?”
Kaminari must be unable to think of any viable response to that, because he flings himself from Katsuki’s grasp and into Shinso’s arms, almost knocking Shinso to the floor with the force of it.
Katsuki doesn’t have time to say anything else before Izuku is grabbing him by the wrist and pulling him through the party. Izuku doesn’t look at Katsuki but Katsuki doesn’t need to see his face to know that he’s upset. To be fair, their conversation was completely derailed by Kaminari and Shinso’s soap opera of a relationship, so Katsuki can’t exactly blame him.
They make their way through the people and then outside. They’re heading back towards their dorms, and Katsuki decides that he’s going to wait until they’re comfortably behind closed doors before he presses Izuku for more information.
They find their way to Izuku’s room and Katsuki lets Izuku get changed in silence. Izuku is breathing heavy and muttering things under his breath, clearly upset, but refusing to talk about it.
Katsuki can’t take it anymore. It comes out angier than he means for it to when he asks, “Are you… jealous? Of Kaminari?”
“What?” Izuku bristles and shifts a little on his feet. He doesn’t meet Katsuki’s eyes. “Why would you say that?”
“I don’t know,” Katsuki says with a shrug. He needs to get to the fucking bottom of this, and he’d prefer to just nip it in the bud if that’s possible. “You glare at him every time he’s around. You’re friends with like, everyone, but for some reason you never want to invite him to movie nights unless I remind you that he’s part of my friend group.”
Izuku is quiet. He makes a face like Katsuki’s backed him into a corner.
“I don’t know,” Izuku says softly after a few minutes. “I don’t think I’m jealous.”
Katsuki doesn’t buy it. “Then what’s your problem with him?”
Izuku fidgets. “I don’t have one?”
“Bullshit,” Katsuki snaps, clicking his tongue in annoyance. “Is it because he hangs all over me? Because if that’s what it is, he does that to literally everyone. I was his target tonight, but he does the same shit to Kirishima—”
“It’s not that.” Izuku bites his lower lip again, something he does when he’s anxious. “I know that he’s like that when he’s drunk. It’s not… It’s not that.”
Katsuki lifts his brows. “But you admit that there is something then, right?”
“I don’t know,” Izuku admits, sitting down on Katsuki’s bed. His leg is shaking anxiously and he starts biting on the skin next to the nail on his thumb.
Katsuki sits down next to him. He reaches out and puts what he hopes is a comforting hand on Izuku’s thigh. This is new to him. Being intimate like this? Talking about feelings? It’s new territory and Katsuki is still scared shitless that he’s going to mess it up.
Katsuki swallows past the dryness in his throat and says, “Come on, Izuku, we’re boyfriends now and you need to tell me this shit so we don’t—”
Izuku breaks. His head snaps up and meets Katsuki’s eyes, tears threatening to fall. “Why do you let him call you ‘Kacchan’?”
Katsuki… Wasn’t expecting that.
“What?”
Izuku’s cheeks are bright red. He blinks and a few tears escape but he wipes them away before they can fall down his face. “You don’t let anyone else call you that. Not even Kirishima, and he’s like, your best friend . Why do you let him call you ‘Kacchan’, when I’m the only one who usually calls you that?”
Katsuki gapes at him. “Izuku—”
Izuku doesn’t let him finish. He goes off like a rocket, ranting the way he always does when he’s overwhelmed. “Did you guys go out? I know I can’t be your first boyfriend. I always assumed that, I don’t know, you and Kirishima had a thing or something, and I get that but I think Kaminari still likes you because he just seems to always want to be around you and I hate how it makes me feel when I see the two of you together and when he says your name like he’s allowed to call you that—”
He isn’t going to stop. Katsuki knows that about Izuku. When he’s worked up like this, he’ll talk and talk and talk until his tongue is bone dry and he’ll still feel like there’s more to say. Katsuki wishes there was a way to tell Izuku that he gets it, he understands, he doesn’t need Izuku to explain everything in every possible way with the hopes that something he says will stick. He hears him.
So Katsuki does the only thing he knows how to do. He grabs Izuku’s face and pulls him in for a kiss.
Not just any kiss either — not just some peck on the lips to pull Izuku out of his own head — no, Katsuki goes hard . He tilts Izuku’s head to the side and presses their lips together. He sneaks his tongue into Izuku’s mouth and licks into him, savoring the bitter taste of vodka that’s still strong on his breath.
“Deku,” Katsuki says softly once he pulls away to breathe. “Shut the fuck up.”
Izuku’s eyes are closed and he exhales slowly through his nose. He presses their foreheads together and his voice is so quiet when he says, “Okay.”
Katsuki holds him there for a few moments. He lets their heartbeats synchronize in the silence of his dorm room. Distantly, Katsuki can still hear the loud music coming from outside of his window, the one that faces the Class B dorms.
Katsuki sighs and pulls back. He feels like he might throw up. He really is bad at this stuff and he doesn’t want to fuck it up by saying the wrong thing. He wishes that relationships were as easy as using his quirk is. He wishes he were just good at it without trying, the way Izuku seems to be.
“I don’t — I’ve never had feelings for Kaminari,” Katsuki starts. “We’ve never done anything. I’ve never done anything with any of my friends.”
Izuku sniffles. “Why not?”
Katsuki sighs again. Every part of him is screaming for him to turn and run, but he stays strong. Katsuki thinks about the answer to that question. Why hadn’t he done anything with the others? They were always playing make out games and being stupid, horny teenagers, but Katsuki always stayed out of it.
There was probably a chance that if he’d given into it, he and Kirishima would’ve been boyfriends. There was tension between them and one time after a smoke sesh, Kirishima had asked him if he wanted to kiss. It was probably just going to be a casual thing, a heat of the moment, passion-fueled weed kiss, but there’s also a chance it could have turned into something else. Katsuki said no because…
“Because they weren’t you?”
Izuku blinks at him, while he waits for the full impact of what Katsuki’s just said to hit him. When it does, he looks like he might cry again. “Kacchan,” Izuku breathes, unsure of what else to say.
“Look, maybe this is my fault because I’m fucking shit at talking about my feelings but…” Katsuki swallows and presses on, ignoring every bell and whistle going off in his head. “I like you, Deku. I’ve liked you for a long time. I’ve liked you longer than we’ve been dating, and I don’t think I’ve ever liked anyone else in the fucking way that I like you.”
“I like you too,” Izuku says. He takes Katsuki’s hands in his. “I really, really do.”
“Then stop being fucking jealous over Denki Kaminari,” Katsuki says with a snort. “He calls me Kacchan because you call me Kacchan and he thinks it’s funny. He does it to make fun of me. It’s not a fucking flirty thing, it’s literally him being a god damn troll.”
“Oh,” Izuku says. He stares at Katsuki and then relaxes a little. “Well I feel like an idiot.”
Katsuki can’t help but smile. He leans in and kisses Izuku gently on the mouth. “That’s because you are an idiot.”
“But you still like me?” Izuku asks, smiling back.
“You tell me.” Katsuki takes the opportunity to climb on top of Izuku. Now that the tension of the drama is over, Katsuki remembers that he’s pleasantly cross faded. And when he’s pleasantly cross faded, there are two things he loves to do.
One: He likes to put his headphones on and listen to music on the balcony of his dorm room. Sometimes, if it’s dark enough, Katsuki can see the stars and it makes him feel comfortably small in a world so big.
And two: He likes to get his fucking back blown out by his boyfriend.
Sex just feels different when he isn’t sober. He loves sober sex too of course, but there’s something nice and intimate about the taste of liquor in Izuku’s mouth and the way his brain gets all wobbly. Katsuki is hard just thinking about it, and when he grinds his hips down against Izuku’s, he can feel that he’s hard too.
It’s effortless; this thing between them. Katsuki always thought that sex would be messy and complicated and awkward, but it isn’t for them. Izuku just knows him. He knows what Katsuki likes without Katsuki even needing to ask. When he kisses Katsuki it’s so gentle when he needs it to be, and rough when he wants it to be. His big hands cup Katsuki’s jaw, his fingers thread themselves in Katsuki’s hair. Katsuki lets himself melt into the touch and comes apart beneath Izuku’s sheets.
“You’re so pretty, Kacchan,” Izuku says, just before he runs his tongue along Katsuki’s bare chest. “God, you’re so perfect.”
Katsuki preens at the praise. He lifts his hips up and reaches down to stroke himself, but Izuku grabs his hands and pins them to his sides.
“No one else is allowed to touch you,” Izuku whispers, his breath hot in Katsuki’s ear. He lifts Katsuki’s arms up and pins them on the pillow right about his head, holding them together with one big hand. With the other one, he reaches down to grab Katsuki’s cock. Katsuki cries out at the touch and tries to buck his hips up into the touch, but Izuku uses his thighs to pin Katsuki into place.
This position is new, and Katsuki loves it. He feels so safe, pinned to the bed beneath Izuku’s powerful frame. Izuku’s hand is gentle and good where it strokes him, nice and slow. He knows just how Katsuki likes to be touched, like he’s inside of Katsuki’s brain somehow, hearing all of his thoughts.
“You’re mine, Kacchan,” Izuku tells him, licking a stripe up Katsuki’s throat and along his jaw. “Mine, mine, mine.”
Katsuki nods and whimpers, drowning in the feeling of Izuku all over him.
Yes.
Izuku lets go of Katsuki’s hands and moves, raking his nails lightly over Katsuki’s body as he makes his way down to Katsuki’s crotch.
Of course I’m yours.
Jealousy is not exactly a good look for Izuku, but Katsuki knows that green has always been Izuku’s color. Maybe it was stupid of Katsuki to not realize that Izuku would be the jealous type, all things considered. The guy pretends to be a saint in front of their classmates, but Katsuki knows from their time in bed that that couldn't be farther from the truth.
When they’re alone, Katsuki gets to see a whole new side of Izuku. He gets to hear Izuku growl and feel Izuku’s fingernails press into his skin. He gets to kiss him and see that hungry look in his eyes and know that Izuku wants him.
Izuku lifts Katsuki’s legs up over his shoulders and takes Katsuki into his mouth. Katsuki bites his lip to stop himself from shouting and grips the sheets tightly in his fists.
Izuku is way too good at this for Katsuki to ever buy that nice guy act again. He’s a fucking freak in bed. He swallows Katsuki down like he’s nothing, doesn’t even gag when Katsuki’s cock hits the back of his throat. Izuku’s eyes roll back like sucking Katsuki’s cock is the best thing he’s ever done and Katsuki can’t help but watch, in awe of the person he chose to be his.
“Izuku,” Katsuki gasps, feeling his climax start to build at the base of his cock. “I’m close.”
Izuku nods and pulls off with a soft, wet pop. Katsuki takes the opportunity to grab the lube from Izuku’s nightstand drawer and toss it to his boyfriend. Izuku catches it and opens the lid, squeezing a generous amount onto his middle and forefinger before using them fuck Katsuki open.
Katsuki closes his eyes and watches as the colors dance behind his eyelids. He relaxes easily into Izuku’s touch, lets himself moan and lets his legs fall open with every brush of Izuku’s fingers inside of him.
He realizes, in that moment, that there is no one else he could possibly want to do something like this. There is no one, not a single person on this planet, that Katsuki would want to see him like this. To touch him like this. To know him like this.
Izuku has nothing to be jealous about because Katsuki isn’t fucking going anywhere. He’s going to stay, right here, for as long as he can.
When Izuku finally rolls the condom on and fucks into him, Katsuki is on the verge of tears. There’s something almost magical about realizing that he isn’t his own person anymore, he’s something shared, something precious. He’s Izuku’s and Izuku is his, and that’s how it should always be.
They fall asleep beside each other, wrapped up in one another’s arms. Katsuki sleeps better than he has in years.
*.*.*.*.*
The next day, Katsuki runs into Kaminari in the bathroom.
Kaminari is hung over and has just finished emptying his stomach through his mouth and is brushing his teeth when Katsuki walks in.
“Hey, Kacchan!” Kaminari says through the bubbles in his mouth.
Izuku walks in behind Katsuki and stiffens a little at the pet name, and Katsuki is having none of that.
“Don’t call me that,” Katsuki snaps. He sets his caddy down on the sinks and turns to give Kaminari what he hopes is a serious expression.
Kaminari spits and wipes his mouth. “Aww, come on Kacchan, you know you like it.”
Katsuki rolls his eyes. “No. I don’t. And I’m serious — stop calling me that. Only my parents and my boyfriend can call me that, and I don’t want people getting the wrong idea about us.”
Kaminari’s eyes flash to the place behind Katsuki where Izuku is standing. His face gets a little pale and Katsuki is worried that he might puke again, but he just swallows and nods.
“Oh,” he says. “Uh, right. Yeah, I’m sorry about that.”
Katsuki feels himself relax a little bit. “Thanks. Now fuck off, I need to use that sink.”
And just like that, things get a little easier. Kaminari makes a squawking noise and throws his toothbrush at Katsuki, which Katsuki catches and throws right back at his stupid face. The playful banter between them is still there.
When Kaminari leaves, Izuku gives Katsuki’s reflection a crooked smile, and Katsuki’s heart feels full enough to burst.