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Izuku collapses back on the couch, between his current load of college classes and nannying for the Bakugous he is exhausted. Not that he doesn’t love working for the family, but they are … weird at times. Mitsuki is a well-known fashion model who works with her husband on their small but successful fashion line. Often that doesn’t leave them a lot of time for family responsibilities like keeping their sleek modern home clean or looking after their elementary school son Katsuki.
Mitsuki is competitive, loud and driven, and while her husband Masaru is quiet he has the same hard-working intensity as his wife. Despite their son only being elementary age, he often fights with his mom, who herself seems to never hold back from arguing with her headstrong boy. Izuku grew up with only his mom and their relationship could not have been more different. Both tended towards being polite to the point of awkwardness, and Izuku couldn’t ever dream of raising his voice towards the sweet woman who raised him.
Earlier that evening Katsuki’s parents had stood at the door giving him one last rundown on their trip outside the country for the next week. While they were gone for a fashion show, Izuku would be watching the house and their son. Izuku had classes while Katsuki was at school and would be able to drop him off and pick him up from school. It is a Friday night, so the homework for his intensive premed classes wouldn’t be due till Monday, and Izuku settles back deeper into the comfortable sofa.
Lazily, Izuku reaches for the remote, turning on a drama he wants to catch up on. Despite the usually enthralling plot lines of the show, Izuku finds it hard to focus on the program. His mind keeps drifting to how Katsuki acted during his nightly bath. When Izuku watched Katsuki during the night he usually only needed to tell the younger boy that it was bath time. Unlike many children his age, Katsuki is often a little fastidious about cleanliness and organization and needs little prompting to bathe himself. This night had been different. Izuku didn’t know if it was because Katsuki was upset about his parents being gone for a whole week, but he refused to bathe himself. Frustrated, Izuku had carried Katsuki into the bathroom and while the boy had followed his directions, he had still refused to actually wash himself, throwing a fit every time Izuku had tried to leave.
Much like his mom, Katsuki didn’t hesitate in making demands of Izuku. He even calls him Deku, the nickname born after Katsuki had first eaten his cooking and told Izuku that he was a Deku since he couldn’t even cook. While it is often annoying to have to deal with such a volatile boy, Katsuki is intelligent and talented. These characteristics often made it fun to take care of Katsuki, despite his opinionated nature. Bright is how Izuku thinks of his charge, not just in terms of intelligence but in how he seems to shine in doing even the most mundane things in his small life.
His eyes in particular captivated Izuku, they are a bright red than often entrances him. Their sharpness often feels like they saw more of Izuku than even most adults. That evening those eyes had been mutinous and distracting, staring at Izuku as he had undressed him and as he had washed the young boy.
After trying and failing to stay engaged with the drama, he turns off the television and throws his head back on the sofa, eyes closed. Izuku thinks about falling asleep in the guest bedroom but dismisses the idea. He is still wide awake, a little restless and, if he wouldn’t have felt guilty about leaving Katsuki by himself, he would go on a run.
There is one thing he could do that would get him in the mood for sleep. Izuku lets his hands drift down to the sweat pants that are tied on his hips and loosens the tie, pulling down them and his boxers to his knees. This late at night Katsuki would be dead to the world, and the idea of jerking off in someone else’s living room is a little thrilling.
With a sigh Izuku starts to rub his palm along his limp shaft, quickly filling with blood at the taboo nature of his location. Eyes still closed he thinks of his usual jerkoff material, the strong forearms of his biology class TA, maybe the soft chest of one of the girls in his study group.
The girl in question often wears deep v-necks which showes off her pale cleavage, the flesh looking plush, jiggling as she often exuberantly moves her arms around when asking questions or getting into a subject. He can image the softness surrounding his length as he presses her breasts together rubbing himself between them. God, the milky pale flesh reminds him of the soft thighs he had soaped earlier that evening, pale and unmarked from the sun or the other impressions left by time- shit, he needs to stop.
He grunts as his callused hand closes over his length and he tries to refocus on the assistant professor that teaches one of his math courses. The man in question has plush red lips that Izuku likes to watch as he talks, and during especially boring lectures he might imagine them wrapped around his cock. He can even imagine the way they would turn bright red, leaving little kitten licks at his head while bright red eyes-
Suddenly, he feels a small grip on his bare thigh, “Deku?”
Immediately letting go of his cock, Izuku jerks and sits up. “Wh- What?!”
Standing next to him, eyes darting between his crotch and his face, is Katsuki. “What are you doing Deku?” Dressed in a big nightshirt that falls to his midthigh, gaze confused, he looks so so innocent and Izuku shudders, his cock twitching.
“Why do you have your pants off? And what’s wrong with your-“ Katsuki’s little hand goes to grab as his cock. Instinctively, Izuku knocks his arm away before that little hand can touch his throbbing length.
“Ah… Nothing… Just adult stuff! You should go back to bed.” Izuku trips over his words, just wanting the boy to leave.
He knows that he made a mistake as soon as Katsuki’s eyes sharpen in curiosity at the words “adult stuff”.
“What kind of adult stuff? Is it fun? It looks weird.” Despite having his arm knocked away earlier Katsuki doesn’t hesitate at trying to grab Izuku again. This time Izuku grabs and holds his arm, the limb is thin in his hand and his fingers easily wrap around his forearm. His hand feels a little sticky, and Izuku realizes the hand wrapped around the boy’s arm was the same one that had been wrapped around his cock.
Katsuki’s expression turns pouting, “Let go of me.” He shakes his arm against Izuku’s hold, one that Izuku barely needs to concentrate on to keep his grip.
“No Katsuki, you need to go back to bed.” Izuku ignores his questions and hopes that will be the end of it.
“No, I don’t wanna! Tell me what you’re doing!!” Katsuki stamps his feet clearly gearing up for an argument or a fit. “I’ll tell mom on you! We’re supposed to wear underwear unless we’re in the bathroom! I’ll tell her you weren’t!”
Izuku feels himself pale, he can’t imagine what Katsuki might tell his mom. Just a couple of questions would led her to finding out their perverted nanny was jerking off on the couch. Then there went his much-needed job. He has to make sure the Katsuki wouldn’t say anything to his mom.
“Look, you don’t need to tell your mom, okay? I was just playing an adult game. It’s really boring.” Izuku softens his voice as he watches Katsuki try to force himself out of Izuku’s grip.
“It doesn’t look like it’s not fun. Games are fun.” Izuku watches Katsuki push out his plump and chapped bottom lip. His eyes note it’s red plushness and he feels his cock twitch again. “Let me play!”
Then Katsuki’s little pink tongue sticks out for a moment as he thinks, “If you let me play with you I won’t tell my mom.” He holds out his pinkie to Izuku, “I’ll pinkie swear.”
Izuku wants to say he really tries, but he sees the determined red gaze met his eyes, face sweet and slightly flushed from Katsuki’s pout, and he quickly crumbles. His voice is slightly hoarse as he speaks, “Okay Kacchan, I’ll play with you, but you have to swear you won’t tell anyone. Okay?”
Katsuki clumsily hides a grin, “Are you calling me a liar? I said I wouldn’t tell my mom, and I won’t tell anyone else!” He waves his hand, “So let’s pinkie swear.”
Izuku holds out his own pinkie that dwarfs the size of Katsuki’s, “If you wanna play, you have to listen to me and do exactly what I say.”
Little face serious, Katsuki nods as they shake their pinkies together, “I swear!” Izuku repeats the swear, a rolling hunger in his gut.
Letting go of Katsuki’s arm he motions towards his cock, “You can touch it if you want, just be gentle.”
The boy holds it with one hand, the size clearly dwarfs the extent of his grip. “Oh! If feels hot.” Katsuki’s gaze trains itself on the length he holds, and Izuku taps his other arm.
“Grab it with both hands.” Katsuki follows his directions and looks back at Izuku’s face.
“Okay, how do I play?” His small hands barely overlap each other as they curve around his cock and Izuku feels ultra-sensitive with the timid grip on his length.
“Just bring your hands up and down like-“ Izuku folds his own hand over Katsuki’s smaller ones, and tightens their grip and guiding them up and down, “this. Yeah, fuck keep doing that.” Izuku leans back and groans, watching Katsuki’s pretty little face tighten in concentration.
Katsuki speeds up his pace and Izuku feels himself twitch. “It moved!” He looks back up to Izuku, “I’m doing it right, its supposed to do that?”
“Yeah, Kacchan you’ve doing a real good job, making me feel good.” Izuku gently thrusts his hips into Katsuki’s grip. “Perfect, Kacchan.”
Katsuki flushes red at the compliment. “Of course I’m doing good Deku! I always win games!” Izuku notices that Katsuki’s arms are already starting to shake, not used to the strange big movements. “So how do I win the game?”
Izuku smooths his palm over the silky fine hair next to him, “You just have to make me feel good enough to come. Then you win Kacchan.”
“Come?” Katsuki shakes off his hand, and tilts his head back to look at Izuku, his voice full of sweet innocence, “What’s that?”
A low groan comes from Izuku’s throat, the question, the voice, the sweet inquisitive face all make his cock throb. “Oh Kacchan, its what happens when you win. You’ll know it happens when,” here Izuku takes one of Katsuki’s slowing hands and guides a finger to his slit, slightly digging into it and groaning again, “ah-white wet stuff comes out of here.”
“So, this is making you feel good?” Katsuki looks a little frustrated as his arms apparently give out on him, “Would it make me feel good too?”
“You’re so smart Kacchan. It will make you feel good too, let me show you.” Izuku kicks off the rest of his sweats and hooks his hands under Katsuki’s arms to pull him up into his lap.
“But I’m supposed to make you feel good! You can’t get me to lose stupid Deku.” Katsuki shifts on his lap, rubbing against his hard dick, almost making Izuku lose it.
“Trust me Kacchan, making you feel good will make me feel good.” Izuku pulls Katsuki’s night shirt over his pale thighs, up his tiny pale chest dotted with two pink nipples and over his head, throwing it onto the ground.
“One of the places that it feels good to get touched is here.” Izuku licks his thumb and smears it over one of Katsuki’s nipples, then slowly swirls around the nub. Keeping a close eye on the boy’s face, Izuku watches as his eyes fall shut and his mouth parts.
“Oh… oh… it feels… its supposed to feel good?” Katsuki struggles to form a sentence.
“Yes Kacchan, does it not? I can stop if it doesn’t feel good to you.” Izuku pitches his voice softly with just a touch of condescension.
“No! Don’t stop it feels… good.” Katsuki continues to squirm on his lap, and Izuku lets himself grind into the softness above him.
“Do you feel that Kacchan?” Izuku makes an especially hard grind into the boy’s underwear with his cock, “You’re making me feel good to. You’ll win in no time.”
Izuku rubs the outside of Katsuki’s underwear, finding a small hardness under the cloth. “Oh Kacchan, see you are feeling good too.”
Katsuki’s breaths grow more labored as Izuku continues to rub the little hardon and play with his nipple until he throws his head back, eyes screwed shut, mouth wide open and shudders. “Deku! Ah ah ah, Deku!”
There’s no real wetness for Izuku to feel through the underwear and as he pulls them off all he sees is a little bit of clear fluid on the flush cocklet. “Kacchan’s such a good boy, coming for me.”
Katsuki looks a little panicked, “Does that mean I lose?”
A wide smile stretches at Izuku’s lips, “No Kacchan, remember I told you that you win when I come. You can come as many times at you want, it doesn’t matter.”
Unbothered by his lack of underwear, Katsuki looks at Izuku, wetness barely hinted in the corners of his eyes, face flushed, and lips already swollen, all probably from his baby orgasm. “I can’t touch you though, like I was doing.”
Chuckling, Izuku rearranges the boy on his bare lap with Katsuki’s back pressed to his chest, slim thighs pressed together on either side of Izuku’s throbbing cock. “Don’t worry Katsuki, this will work just fine.”
“What do I need to do Izuku?” Katsuki seems a little unhappy not being able to look at Izuku.
Taking Katsuki’s hands he puts them over his cock head that pokes lewdly through the boy’s thighs, tight against his small hairless ball sack and cocklet. “Just keep your thighs tight together and rub the top of my penis when you see it. Okay Kacchan?”
Izuku feels the thighs tighten around him and the small hands get to work rubbing at his cock, “Obviously Deku, I’m gonna win!”
Izuku braces one arm against Katsuki’s chest. He has never thought of himself as an especially hairy man, but the way his broad forearm’s dark hair contrasts against Katsuki’s hairless chest makes him seem relatively grizzled. He then takes his other arm and hooks it beneath Katsuki’s knees, holding the boy slightly suspended over him. Katsuki barely weights anything like this and when Izuku pushes forwards with his hips, he has to muffle himself in the boy’s shoulder.
“Oh Kacchan, you feel perfect.” With how much precome Izuku has been leaking, the slide is wet, smooth, tight. Blissful. Grunting as he thrusts, Izuku looks over the boy’s shoulder and almost comes from how fucking perfect his big angry red cock looks fucking between those small beautiful thighs. Turning his head, Izuku starts leaving wet kisses along Katsuki’s throat and the side of his face, careful to not leave any marks.
“Deku, you’re making me wet. It feels gr-“
Izuku cuts him off, “Good right? It feels good, just like how you’re making me feel.”
Katsuki whimpers and Izuku watches his little cocklet harden, probably from the friction of him rubbing himself against it. Izuku steadily increases his pace, his thrusts starting to rock Katsuki’s body wildly as he gets himself off between the boy’s thighs.
“Deku!” Katsuki cries out as his tiny bodies convulses and shakes through another undeveloped orgasm. His tightening thighs and cries make Deku’s orgasm slam into him like a truck.
“Kacchan’s such a perfect little boy. So good, so pretty. Fuck. Yes, Kacchan’s so good.” Izuku watches as his come shoots out and sullies the little boy in his lap, the sight almost making him come again. Without thought he takes one of Katsuki’s hand and puts it up to the boy’s mouth.
“Help me clean up the mess you made.” Katsuki looks at him his eyebrows pinched.
“Didn’t you make it? Also, it looks gross.” Katsuki tries to pull his hand out of Izuku’s grip.
Izuku laughs lightly, “Of course you made the mess, you made me come. You won the game, right?” Izuku guides the hand closest to him into his mouth, fitting the entire thing into his mouth letting his tongue clean his own come from between Katsuki’s small fingers. “See, it doesn’t taste bad.
Dropping the newly cleaned hand, he brings the other one back to Katsuki’s face. The boy cleans the mess off his own hand, face twisted into a grimace. The sight makes Izuku want to take the boy and throw him onto his bed. He wants to take every one of Katsuki’s firsts.
But then Katsuki yawns and Izuku realizes he needs to put the boy to bed, the time already too late. Katsuki was at his most cranky when he doesn’t get enough sleep the night before.
Izuku cleans up the boy, wiping off his little cocklet and thighs, cleaning off any stray come, and redresses him. As he tucks Katsuki into bed he kisses the boy on the forehead, “So what did you promise?”
“I won’t tell mommy anything.” Katsuki’s voice is soft with sleepiness and he slides into using more childish words with his exhaustion. He struggles to keep his eyes open as he looks at Izuku, “I won right? I did good.”
Izuku smiles gently at the boy, “Of course you won Kacchan. You were amazing.”
As he shuts the door quietly behind him, Izuku lets the smile turn into a wide grin. Kacchan wouldn’t be happy with just winning a game once, but there would be plenty of more opportunities to play it this week.