Chapter Text
“Oneechan? Can I… can I touch your boobs?”
Well, that’s certainly a question Dia isn’t expecting to hear from her timid little brother, one that quickly brings a blush to her face. Her immediate reaction was almost to slap him and call him a pervert, but she quickly restrained herself, reminding herself that Ruby doesn’t know any better, and that he’s most certainly just curious. After all, he’s still such a young, sheltered boy.
“W-well… I suppose you may.” Dia says, still rather nervous about this, as this IS incest, after all. Or, no, it isn’t! Since Ruby doesn’t know any better, this is just a learning experience for him, that’s all it is! He doesn’t even know what sex is yet! At least that’s how Dia tries to reassure herself that this is okay. Putting her hands at her hips and puffing out her chest, she says, “Go ahead, Ruby.”
Cautiously, and with a shaky hand, Ruby timidly reaches forward and places a hand upon Dia’s breast, and then, upon contact, immediately lets out a small squeaky gasp, as if surprised by the sensation. His face turning just as red as his big sister’s, he slowly cups the other breast with his other hand. Clearly not really knowing what he’s supposed to do next, he just kind of, cups his big sister’s breasts in his hand, not really doing anything with them.
“...Well? Um… are you… a-are you satisfied?” Looking away in embarrassment and shameful arousal, finding her little brother touching her breasts to be so much more exciting than she had anticipated, Dia asks, both wanting him to stop and wanting him to keep going. No, this is just for the sake of exploration, there’s no use getting aroused from this! It wouldn’t be right to anyways. He’s her little brother! “Are you done, Ruby?”
“O-oh! I-I’m sorry, oneechan… I’ll, I’ll s-stop…” Quickly pulling his hands back and putting them behind him, Ruby looks down, apologetic, as if he’s gotten into trouble for something. A gesture that, Dia is too ashamed to admit, she finds to be… incredibly adorable.
“Oh no, no, I didn’t mean to… oh Ruby, I’m not scolding you, I’m not mad at you.” Dia quickly reassures Ruby, not wanting him to feel bad. Although she was previously ashamed and hesitant about this, seeing her little brother acting so innocently seems to have flipped a switch in her, endowing her with a renewed sense of… confidence? Morbid curiosity? Dia isn’t sure, but it’s something that’s making her want to keep going. “It’s okay, you can touch my boobs some more if you’d like, Ruby. You’ve barely just begun, after all.”
“Barely just… begun…?”
Taking her little brother’s hands, Dia brings them up to her chest once again, setting Ruby’s hands upon her breasts before letting go of them. Giving him a soft smile, this time making eye contact, she tells him, “Why don’t you try squeezing them, hmm?”
“Squeezing them…”
Doing as he’s instructed, Ruby slowly starts to grope Dia’s boobs, curling his fingers into her soft flesh and squeezing them with his hands, and immediately, he gasps, as if discovering a new sensation with which he’s unfamiliar. His cheeks once again turning red, he continues moving his fingers, squeezing and groping his oneechan’s boobs, before getting curious and starts rubbing them together, against each other.
As her little brother plays with her chest, Dia grows more and more excited, her body hot, her breathing heavy, her thoughts corrupt. It’s okay, she’s just letting Ruby explore, there isn’t anything lecherous or incestuous about this, it’s fine… That’s just what Dia keeps telling herself, that she isn’t doing anything suspect or depraved, that this is something Ruby has to learn sooner or later anyways, so this is okay. There is nothing wrong with what she’s doing.
“O-Oneechan… w-wow… these are… your boobs are really soft…” Ruby stutters, his own breathing getting heavy as well as he becomes noticeably aroused, a little tent forming in his shorts as he becomes entranced in groping and fondling his big sister’s boobs. “I-I… I want to become a girl when I grow up too, oneechan… j-just like you…”
Oh my! This certainly isn't the development Dia has been expecting, but it certainly isn't unwelcome either, the idea of Ruby as her little sister instead of her little brother... Aah, but of course, this is all part of helping her little brother explore, that's all there is to it. That's right, there is nothing morally depraved about what she is about to do. She has an egg to crack, after all!
"Ruby... hmhm, if you want to be a little girl, I can teach you what little girls do." Dia says, her voice lowered to a sultry whisper, as she draws in a bit closer to her little brother. Reaching down, she gropes at the little tent in Ruby's shorts, getting a surprised squeak out of him, and gently rubs it with her hand. "After all, this is something you'll have to learn to do when you grow up to be a girl..."
"O-oneechan-!?" Ruby gasps, almost recoiling reflexively if he isn't so absorbed in groping his big sister. But the new and shocking sensation certainly still has his body tense and excited, as his little pecker becomes even harder in his sister's hand. "B-but that's... th-that's my p-peepee..."
"Hmhmm, tell me, Ruby. When does your peepee usually become hard and stiff like this?" Dia asks, pulling his shorts and undies down enough to get a good view of his cute little boner, before resuming to rub it in her hand. It's okay, this is absolutely permissible, she's just giving him the sex ed she knows their parents would never give him. She is only doing her sisterly duties.
"A-aah, it... o-oneechan, it, um, it... usually gets... l-like that, when um... when..." It's hard to tell whether Ruby's having such a hard time articulating his thoughts because of embarrassment or because of arousal from his oneechan effectively giving him a handjob while he fonds her chest, but it's something Dia finds to be absolutely adorable. "...wh-when I... wh-whenever oneechan... o-or... or mom... gives me a hug... and I get to... and I get to sniff..."
"Ohhh? My, that's so cute..." Goodness, the more Dia discovers! Poor Ruby, having all these feelings for his mommy and his oneechan that he never gets to express nor understand... That's why as his big sister, Dia's going to change that for him, just as any good oneechans ought. "Why don't oneechan teach you how to make it go back down, hmm?"
"You... y-you can do that, oneechan?"
"But of course! If you want to become a good little girl, Ruby, you're going to have to learn to do this well too. So pay close attention to how I'm touching your peepee, okay?" Dia instructs, as she kneels down before her little brother, at a height where he can't grope her anymore, and starts focusing on stroking his cute little member. Such an adorable little penis on a little boy like Ruby, its foreskin isn't even peeled back yet... "When you feel good enough, this white stuff will come out of your peepee, and then your peepee will go back down."
Taking Ruby's dick in her hands, Dia slowly starts pulling his foreskin back, the undoubtedly overwhelming sensation causing Ruby to shake and squeal, "O-o-oneechan...! A-aah, th-that's too m-much...! It h-hurts!"
"It's going to be okay, Ruby, oneechan's not going to hurt you." She says calmly, recognizing that maybe Ruby's not ready yet to have his glans fully out, and stopping about halfway there. She doesn't actually know what that feels like, but if it's getting to be too much for her little brother, she decides it's better not to overwhelm him. So instead, she returns to running his dick, wrapping two fingers around the base of his shaft and moving them up and down, jerking his cute little penis like this. "How does this feel, Ruby? Does it feel good?"
"Y-yes... o-oneechan...! It... a-aahn, it f-feels really g-good..." Oh, how cute of Ruby to be so ecstatic over a simple handjob! He's all hunched over his oneechan, holding onto her shoulders and all, just to keep himself up! "A-ahh, oneechan... i-it feels like... like s-something is going to come out...!"
Excited, Dia speeds up her stroking and, just as the first dribbles of white start to come out, pulls back Ruby's foreskin once again, as much as she wouldn't hurt him, to turn his cute little dribbles into energetic spurts, one of which even jumping up as high as landing on her face. The rest simply ends up landing on her arm or dribbling down onto her hand.
"Oh... oh my...~"
"O-oneechan! I-I'm so s-sorry! I didn't mean to get... to g-get it on your face..." Ruby apologizes, fretting about the mess he's made but not really sure what he can do in this situation, especially with his dick still in his oneechan's hand. "I'll... I-I'll go get some tissues!"
"No, no, that's okay Ruby, calm down." Dia says calmly, letting go of her little brother's penis and bringing her hand to her face, taking a moment to marvel at the sight of her little brother's cum on her. Giving it a lick, she gives Ruby a smile and says, "Hmhm, see? This is the white stuff I was talking about. This is called 'cum', and it tastes very good, you know ~"
"R-really...?"
"Here, try it ~"
Dia brings her hand to Ruby's face, and watches as her little brother cautiously puts his tongue to it, licking at his own semen the same way his oneechan did, tasting it the same way his oneechan did, and swallowing it the same way his oneechan did. His expression is one of curious confusion. "It tastes kind of weird..."
"It's an 'acquired taste'. Do you know what that means?" She asks, licking some more off of her hand as Ruby shakes his head. "It means it's something you'll grow to like. As a girl, it's very important that you grow to like doing this, so why don't you lick the rest of this off of me, Ruby?"
"E-even... even off your... your face...?" Ruby asks, nervous as he starts putting his tongue to his big sister's hand again, getting it nice and clean and swallowing as much of his own cum as he can.
"That's right, even off of my face."
Aah, teaching her little brother to do something so filthy, getting him to lick his own cum off of her hand, her arm, and now her face too... Dia has to admit to herself, maybe this is pretty incestuous after all, since this isn't just about exploring anymore. But, she really doesn't mind. In fact, if anything, she's actually pretty excited that she has a cute little trans sister to play with now...