Chapter Text
Izuku has been obsessed with Katsuki for as long as he can remember.
No matter how poorly Katsuki treated him, no matter how many insults he hurled, Izuku chose to see the good in him. After all, Katsuki’s positive qualities shone like diamonds.
Brash. Courageous. A natural-born leader. Katsuki stood tall without giving up his trademark smirk, pants riding low. Izuku frequently found himself searching for the waistband of Katsuki’s boxers, nostrils flaring when he caught snatches of color.
“Pretty,” Izuku mumbles, talking to himself.
Every flutter of dark lashes, every flex of muscles. Katsuki’s dedication to football inspired Izuku to spend his hard-earned allowance on a gym, copying as much as he could. He dreamt of running with Katsuki hand-in-hand, having Katsuki to himself if only for an instant.
Abruptly, the dream becomes a reality.
Izuku gets greedy.
It’s hard not to get carried away, especially when Katsuki makes such sweet sounds. “Damn you,” Katsuki moans, sweat gluing blonde hair to his nape. It’s darker in the back, cropped close to his skull, but it’s lovely, all the better for Izuku to sink his teeth into while Katsuki fidgets, selfishly fisting his own cock.
They haven’t crossed the line yet, but it’s not out of lack of desire. Izuku wanted it to be official.
For all intents and purposes, Katsuki is his girlfriend.
Logically, Izuku knows that Katsuki is a boy. They had the same parts. Similar sorts of hair. No breasts to speak of, although Katsuki’s pecs came dangerously close. It was a ridiculous line in the sand. These days, coming out wasn’t a rarity.
Still, somehow, it’s easier to think about it in those terms. One of them had to be the boyfriend, and given Katsuki’s proclivities, it would be Izuku.
That’s why it’s such a betrayal when Katsuki gets a girlfriend. Not because he cheated on Izuku—they never established boundaries—but because Katsuki goes out with a girl. Izuku wouldn’t have taken it any better if Katsuki had another boy on his arm, but it felt wrong and it looked wrong. Katsuki wasn’t happy with Crystal. She was an interloper. A means to an end. A stopgap measure.
Izuku jerks off alone in his room, furious. It’s impossible not to conjure Katsuki’s features, all too aware of the things Katsuki would say if he could see Izuku. Sucker. You fell for my trap hook, line, and sinker. You’re no better than anybody else.
He ejaculates, but it’s a disappointing release, missing Katsuki’s mouth something fierce. It was only ever meant to be temporary, but he wanted it to be special.
Izuku wanted Katsuki forever.
Staking a claim wasn’t impossible. Izuku had a good relationship with Katsuki’s parents, maneuvering his way into Katsuki’s room. Katsuki was too observant to let an intrusion pass even if Izuku did his damnedest to cover his tracks.
He would start off small, rearranging Katsuki’s things. Reminding Katsuki that he was still paying attention.
Unfortunately, he gets distracted. It can’t be helped. Izuku’s only sixteen, after all. He swallows, hovering over Katsuki’s hamper. It smells like something curled up and died, stale sweat and day-old grime. Izuku digs until he strikes gold, holding up the fabric until it’s tantalizingly close to his nose.
With the room to himself, he gets carried away. Izuku thinks about calling Katsuki, then he thinks better of it, losing himself in his thoughts. Katsuki’s scent is everywhere. In his room, concentrated in this flimsy piece of fabric. Izuku slinks a hand into his pants and it’s game over, freezing when the door squeaks on its hinges.
“Kacchan,” Izuku mumbles, unable to get his tongue to cooperate.
No matter what, Katsuki is going to murder him, so Izuku decides to push his luck. Miraculously, Katsuki doesn’t so much as threaten Izuku, as eager as he is to pick up where they left off.
This incident gets swept under the rug like all of their trysts—that is, until Izuku manages to talk Katsuki into spending time with him on the weekend.
“If we keep doing stuff like this at school, we’re going to get caught,” Izuku mumbles. While Katsuki would get off scot-free, Izuku sure as shit wouldn’t.
Katsuki concedes on the premise of getting laid without prying eyes, agreeing to meet Izuku at his apartment. Izuku fidgets in the elevator, mind moving a mile a minute.
He might have been granted a pass for sniffing Katsuki’s underwear, but this was another matter entirely.
Izuku contacted a classmate discreetly, paying Nicky off to steal his sister’s uniform. He promised to return it laundered, blasé about the conclusions Nicky drew.
Impatiently, he waits for Katsuki to kick off his shoes. Izuku locks the front door, padding down the hall until they arrive at his room. He’s beet-red as he ducks his head, mindful of Katsuki’s imposing stature, arms folded over his chest.
“Since we’re, um.” Izuku falters, unsure how to refer to their arrangement. After a beat, he forges ahead, clearing his throat. “It’s been a year, so I wanted to try something new.”
It was unusual for him to take initiative, so unusual that Katsuki frowns, taken aback. “Spit it out.”
Instead of answering verbally, Izuku pivots on his heel, rifling through his closet. It’s impossible to miss the two-piece, a blue and white number with no frills, an unmistakable cut, and a zipper Katsuki wouldn’t be able to use.
His waist was a tapered thing, broad shoulders terminating in an hourglass shape. Izuku is expecting it when Katsuki throttles him, yelling at the top of his lungs. “You’re out of your damn mind.”
“Just once,” Izuku mumbles, wheezing through the pain. “Please, Kacchan? Please?”
Katsuki releases him with a scowl, waving the hanger in Izuku’s face. “Do I look like a girl to you?”
Izuku’s knee-jerk answer is obviously not, but his traitorous mouth says, “You’re prettier than any girl at our school.” He claps a hand over his mouth, berating himself for letting that thought slip loose.
Katsuki, meanwhile, is unnerved, lost in disbelief. It’s not like he thinks Izuku is lying. He’s just delusional.
Briefly, Katsuki considers the possibility of insanity being a transmissible disease.
In the interest of getting it over with, Katsuki unbuckles his belt. Izuku watches with rapt attention, captivated by the rustling. The button-down follows his jeans and Katsuki peels his undershirt off last, dusky nipples pert under the A/C. The croptop isn’t a problem, even if he stretches the fabric thin, Aldera spelled out in blocky capital letters.
The skirt is the problem. There’s nothing Katsuki can do about his junk, too low to be hidden by anything. It hangs on his hips, resting peacefully. Izuku drinks in the sight, praying to a god he doesn’t believe in.
His vision goes white when Katsuki kicks him in the shin. “You’re hard. Of course you are.”
Izuku whimpers, pleasure-pain thick in his veins. “You look good,” he insists, hoarse. Reedy.
“Don’t get carried away, loser. M’not your fucking girlfriend.”
This phrase alone is enough to put Izuku’s heart in his throat, twitching at the concept. Kacchan. Girlfriend. Mine.
He tackles Izuku to the mattress. “Are you listening to me?” Izuku nods without thinking about it, feeling Katsuki up. “Useless piece of shit.”
Izuku agrees with a hum, grip hard enough to bruise. Katsuki is delectable like this, sharp planes of skin exposed in the flimsy costume. As much as Katsuki tries to disguise his own arousal, Izuku can feel it, salivating over the concept of getting his dick wet.
Flipping Katsuki over is an inevitability, a necessity to give Katsuki what he wants. They’ve found that lotion mixed with grease made finer lubricant than either substance on its own, bottles shoved into Izuku’s nightstand for safekeeping. He shoves slick fingers inside without taking Katsuki’s boxers off, reveling in the bellowing sound Katsuki makes, lips parted, expression soft.
“Kacchan,” Izuku murmurs, rubbing at Katsuki’s sweet spot, nailing his prostate until he’s pliant and gooey, on the verge of dribbling. “S’that feel good?”
“Shut up,” Katsuki hisses, following Izuku’s line of sight. Izuku is stuck on the deep V where Katsuki pecs peek out, chest paler than the rest of him. He kisses Izuku to keep Izuku from latching on, knowing good and damn well the uniform belongs to someone else.
Izuku fingers him until Katsuki gets sick of it, flipping the skirt for easy access. “You are an embarrassment,” Katsuki jeers, words contrasted by the pose: face down, ass up.
Intelligently, Izuku chooses not to remind Katsuki that Katsuki came of his own volition. He came to Izuku’s apartment for the express purpose of having sex and Izuku followed through, licking a trail up Katsuki’s spine to hear him hiss.
Eventually, the clothes get in the way. Izuku peels Katsuki out of them carefully, lingering on Katsuki’s nipples. It’s a slow burn. Katsuki is tight around him, closeted size-queen that he is. Izuku doesn’t like to think about the possibility of Katsuki breaking up with him, but there is a sick sort of satisfaction in knowing Katsuki would be hard-pressed to find someone his size.
The odds were probably better in the league, but still.
Izuku fucks Katsuki until Katsuki is breathless with it, sweating bullets in Izuku’s sheets. Distantly, Izuku cherishes the prospect of rolling around in Katsuki’s funk, smelling like him for the rest of the day.
He’s yanked out of his daydream by a tug on his arm. “Go piss and shower. I’m gonna throw these in the washer.”
Mourning the loss, Izuku obeys, flopping beside Katsuki on the couch as soon as they’re both clean.
Katsuki waits until the TV is on to talk again. “A year, huh?”
“Mm.”
“You wanna go to prom with me or somethin’?”
Izuku freezes. Honestly, the thought didn’t occur to him. He knew Katsuki wanted to go pro. Their relationship could never be anything more than an open secret.
As always, Katsuki’s bravery inspires him. Tentatively, Izuku reaches for his hand, interlacing their fingers. He expects Katsuki to shake him off, so it’s encouraging when Katsuki squeezes, firm and sweet. “S’alright. This is more than enough for me.”
Katsuki grumbles, but the fussing doesn’t last long. They wind up dozing, pulling away when Inko comes home. Izuku sees Katsuki off with a chaste kiss which Katsuki makes lewd, sticking his tongue in.
Dazed, Izuku watches him leave, shutting the door with a wobbly smile.