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Katsuki’s heats are a nuisance at best and debilitating at worst. He especially hates being told he has to take time off by Deku of all people.
“It’s just for a few days, Kacchan,” he says, voice pitched low and comforting, as if Katsuki’s gonna fight him on it.
It’s the right move, he knows. It always is.
Izuku’s eyes bore into him with that heart-palpitating world-stopping shine that’s been haunting Katsuki all their lives, and Katsuki pretends it’s his omega’s fault when his gut goes on a rollercoaster ride.
He makes a show of giving Izuku the finger as he walks out of their office and slams the door shut, even if he doesn’t mean it.
If Izuku rolls his eyes, Katsuki doesn’t look back to see it.
—
They’ve always been compatible. Katsuki doesn’t share his heat with anyone because his omega has always flinched away from any other alpha’s touch. It’s easier this way. Alone.
The physical pain from his heat is easier to bear than having to chance asking Izuku and getting rejected. He’ll endure a thousand heats before he has confirmation that Izuku loves him as a friend and nothing more. That the care he extends to Katsuki is more than anyone else would ever give him—more than Izuku would give anyone else—but less than what Katsuki wants, needs, craves. Katsuki’s special, but not in that way. He’s always known that.
Izuku might chase after him, but Katsuki’s the one who’s on his heels. He’s always been Izuku’s in every way that counts, and this is the natural continuation of that.
—
His hero costume clings to him like a second layer of skin, uncomfortably damp.
No wonder.
Izuku has a sense for when Katsuki’s heats are about to hit him, before they happen. Before Katsuki knows it, even. It would be useful, given how irregular and untrackable the cycles can be, if it wasn’t so damn annoying.
Now Katsuki knows why yesterday’s shift left him feeling exhausted to the bone, and why waking up early this morning was more torturous than it normally is.
It’s fine. Not a big deal. He’ll go home and sweat it out like he always does.
—
Izuku is gentle with his touch, and generous in how he gives it. Maybe it wouldn’t hurt so much if Katsuki didn’t have to be a firsthand witness to it; to how enamoured everyone is by him. The Midoriya Izuku effect, or whatever Katsuki’s dumbass friends want to call it.
One smile, and they’re a goner.
Katsuki gets it.
—
Summer is Katsuki’s favourite season in every other way, but it fucking sucks whenever he has to deal with this.
He grabs a pack of frozen peas from his freezer and holds it to the back of his neck, then opens his fridge and sticks his head inside when that doesn’t seem to help.
Goddamnit.
He has enough sweat built up to detonate a twelve-story building, and he’s not even allowed to use it to punch the shit out of some villain.
Fuckin’ Deku. (It’s not his fault, Katsuki knows.)
Speaking of. It’s almost eight thirty; which means Izuku’s shift is long over. Which means…
Ding.
There. Of course. Katsuki knows to expect it by now.
—
Izuku doesn’t do this for any other omega, as far as Katsuki knows. Katsuki clings to this knowledge like his life depends on it. He doesn’t dare ask if it’s a matter of opportunity, but as long as Izuku has no interest in checking on another omega during their heat, Katsuki’s going to revel in being the only one.
He doesn’t ask Izuku for more, but he won’t ask him to stop either. He’ll take as much as Izuku is willing to give, because that’s exactly how much he deserves.
—
Katsuki sighs and makes his way to his front door, pack of peas still held to his neck even though it’s not helping.
Doesn’t even need to look through the peephole to see who it is.
“What’d ya want, Deku?” he asks, even though he knows. Katsuki doesn’t understand why Izuku even bothers to ring the doorbell. He has a key, for fuck’s sake.
Izuku holds up a plastic bag. “Can I come in?”
Like Katsuki ever tells him no.
In the living room, Katsuki plops down onto his couch and waits for Izuku to do his thing.
He isn’t wearing any scent patches because—well.
Why should he? He lives alone, and it’s not his problem that Izuku likes to visit when nobody’s asked him to.
And a part of him, a secret twisted part of him that he pretends doesn’t exist, is so pleased in observing Izuku as he takes in Katsuki’s heat scent. The way his pupils dilate; his control ironclad as he acts like he isn’t bothered. Or turned on.
But Izuku’s never shown any interest beyond that of which he cannot control. Not in a way that mattered. ‘Course the omega pheromones get to him, but he’s always the fucking perfect gentleman about it, and it pisses Katsuki off to no end.
“I got you protein bars. I know you don’t like them, but just in case you don’t feel like cooking… Some painkillers. Oh, and those drinks that you like!”
God.
Katsuki can’t look away from him.
Freshly showered, hair still wet in places. Or maybe it’s the sweat. He probably ran instead of taking the train like a normal person. Plain soft blue t-shirt hanging off of him because he doesn’t know how to buy clothes his size.
Katsuki’s head throbs with how feverish he is. Heart pumping blood to all the wrong places.
“Kacchan, are you okay?”
It’s not fair.
—
Daydreaming is not a crime, and even if it was, Katsuki has long learned how to cover his tracks.
No one else is privy to the kind of thoughts he has at night, as he lies awake in a cold bed, wanting to be touched by scarred hands; held in green eyes. Fantasy Izuku’s lips part as easy praise falls off them, and Katsuki leans up in his dream to catch a hold of their warmth.
Their scents make up for a sweet cup of coffee on a spring day, but Katsuki doesn’t need all that. In his dreams, it’s not about his omega needing Izuku’s alpha.
Izuku put a fence around a corner of Katsuki’s heart and marked it with a sharpie, before they even presented, before Katsuki knew what any of it meant. He called it Kacchan. And Kacchan needs Izuku more than anything else.
Heat or no heat, summer or winter, lain bare and flayed open.
—
Izuku kneels between Katsuki’s spread knees on the couch and feels his forehead.
“You’re really warm.”
“No shit,” Katsuki snorts, but it comes out weak.
“Oh, Kacchan…”
Fuck.
Why does his voice have to be so soft?
Izuku pries the melted peas out of his hand and places it on the coffee table before focusing his eyes on Katsuki again.
Warm, so warm. Everything about him is. And Katsuki’s supposed to be the one in heat.
Izuku frowns and his hands land on Katsuki’s cheeks this time, thumbing under his eyes.
“Something’s different this time.”
Katsuki shrugs. All his heats hit him differently. The only common thread is that they’re annoying as fuck and disrupt his routine.
Izuku’s sticking around longer than usual this time time. That can’t be helping. Normally, he leaves the stuff near Katsuki’s feet and awkwardly scrambles away like the nerd he is. Probably (rightfully) worried about his alpha taking the wheels in the face of Katsuki’s heat scent.
“Where’s your nest, Kacchan?”
—
For as much as Izuku sticks his nose in places he doesn’t belong, he’s never seen Katsuki’s nest before. It’s an invisible line he hasn’t crossed; that would be too much.
Alphas need to be invited in, and Katsuki has never taken that step.
His nest is nothing special. The rational part of his mind knows Izuku wouldn’t care, but his omega won’t shut up whenever ‘Izuku’ and ‘nest’ pop up into Katsuki’s head in the same sentence.
Alpha needs to like it. Not good enough. We need to fix it. Fix it. Fix it. Fix—
His nest is fucking fine. He has a pillow and a blanket, and an old hoodie he stole from Izuku years ago, when they were still at UA. He doesn’t show it to anyone else because he knows what they’d say.
His mom doesn’t even need to see it to know. He hates that she can read right through him, but at least it’s her and not anyone else. She understands his need to keep his pride intact better than anyone.
“Why don’t you try, Katsuki? Stop fixating on him and focus on yourself.”
It’s easier said than done when that’s what he’s been doing all his life.
—
Izuku’s hands are rough with scars and cooler than Katsuki’s heated skin. They massage down his neck and rub into his sensitive scent glands, and Katsuki gasps involuntarily at the sharp pang it sends down his spine.
Fantasy Izuku is never so bold. He takes his time, eases Katsuki into it with teasing touches.
“Is it in your bedroom?” Izuku asks.
Katsuki tilts his head up towards his voice. Izuku remains patient for an answer, so Katsuki takes his time with it.
His hands stay.
Katsuki never wants them to go away.
—
Their relationship has been a confusing mess for as long as Katsuki remembers, but even more so since they presented in their teenage years.
Katsuki likes scenting Izuku, and Izuku lets him.
Izuku likes putting a possessive arm around Katsuki’s shoulders when another alpha leers too close. Fire licks Katsuki’s insides in the best way whenever that happens.
He may stand an inch or two taller, but Izuku could drag him down to hell if he wanted.
—
There’s no escaping Izuku’s watchful eyes. Katsuki can’t lie to him, and his silence is enough to damn him.
Izuku’s eyes widen slightly, and he licks his lips, then lets go of Katsuki’s shoulders to hold his hands. Between their bodies, in Katsuki’s lap.
“Kacchan, you have to,” Izuku says. “When was the last time?”
The last time that, what, Katsuki built an actual proper nest? One that wasn’t just his bed with a random sweater thrown on it to make him feel like he wasn’t lying to himself about suppressing his instincts?
Years, probably. But if Katsuki tells him that, Izuku’s eyes are gonna get all twisted with pity, and Katsuki doesn’t fucking want that from him right now.
Katsuki has no right to still be affected so much, anyways.
It’s hard to breathe already, the air stifling and sticky in his throat. Izuku’s too close for comfort.
Katsuki wants to get another pack of peas, but that would mean pushing Izuku away and—he doesn’t want that either.
He leans his head back on the couch and rests his eyes.
Any second now, Izuku’s gonna figure it out. He’s gonna see through him, and then he’ll want nothing to do with Katsuki. He’ll stop coming over to check on him, won’t touch him anymore. Won’t let Katsuki scent him all over even though it’s inappropriate because they’re—nothing.
—
They’re nothing.
—
Katsuki’s eyes burn, and Izuku can’t, can’t, see that.
“Kacchan.”
Katsuki doesn’t answer. It doesn’t matter.
Izuku’s scent grows more concerned, overbearing, then calm again.
His hands hold Katsuki’s tight. Izuku’s always had nice hands. Nice to hold, nice to look at. Wearing battle scars proudly and calloused with hard work. Katsuki’s grateful for how close they are. He remembers a time where he was agonizing about whether or not he’d be entitled to it, to even a simple touch, to calling Izuku his friend. Izuku’s never pushed him away, not once, but he doesn’t know what’s good for him either.
Katsuki’s no good.
He’s crying before he knows it. Fat tears rolling down his cheeks and face pinched uncomfortably to keep his sobs inside his chest. Izuku’s hands are on his face again, gently wiping away the tears.
“You’re crying…”
God, why is he like this?
“Sh-shut up.”
This is pathetic. It’s the heat getting to him. He’ll be fine if Deku just lays off.
He doesn’t though; he keeps touching Katsuki all soft and tender and attentive, and it unravels Katsuki in ways he’s not ready to contemplate, dragging more tears to the surface.
“You’d feel better in a nest, Kacchan.”
A nest, not his nest. Maybe he’s finally caught on that this is another thing Katsuki sucks at.
“I’m fine,” Katsuki chokes out. “Just go a-away.”
“Not a chance, Kacchan. You’re hurting. I’d never leave you like this.”
He’s so offended; it would be funny to see the indignant look on his face under another circumstance. Now, Katsuki can only squirm under his gaze because he doesn’t have it in him to really push Izuku away.
Izuku’s expression softens again, biting his lip. His eyes wide and sad and—Katsuki doesn’t want to look at them anymore, but he can’t look away either. Lost in them. The tears come and go and blur his vision, but it doesn’t matter. Izuku is the one constant.
He hops off of Katsuki’s lap, then slides his hands underneath Katsuki’s knees and back before Katsuki can protest, heaving him into his arms easily.
It pushes Katsuki’s nose into Izuku’s neck, and his scent is intoxicating at the source.
It was muted before, overpowered by Katsuki’s own. But this close Katsuki catches every note, every emotion. The worry and adoration and every ounce of protectiveness that Katsuki doesn’t need but breathes in like he does.
A few hours ago it would have pissed him off. It did. Izuku sending him home ‘for his own good’ always does.
But held close like this, it doesn’t feel like Izuku’s looking down on him. He just—
He just loves him.
Izuku squeezes him one last time, then gently lays him on his bed. He tucks Katsuki in his blanket, and Katsuki doesn’t complain even though he’s too fucking feverish to want one.
—
One time, when he was having a really bad heat, he called Izuku on a whim. Izuku had already done his part; the visit, the goddamn snacks and drinks and a promise to check in again after his cycle. But he still picked up the call on the first ring.
Katsuki couldn’t speak coherently. He doesn’t remember what he mumbled, but it must have made some sort of sense because Izuku stayed on the line and talked to him about nonsensical nerd shit for a whole hour.
Katsuki wishes he remembered the words, but all he remembers is the warm feeling in his chest as he fell asleep to the sound of Izuku’s soft voice.
—
“What’re you doing?” Katsuki asks, the syllables dragging, lids heavy.
He’s pulling shit out of Katsuki’s closet at random. It’s embarrassing—he’s gonna see the hero merch Katsuki hoards in the back.
A Red Riot hoodie is first. It smacks Katsuki in the head.
“What the—”
Oh. He scented it. It’s all…pine and green apples and petrichor. Like he’s outside in cool spring air taking a hike through a nice natural trail. Another deep breath, and he’s in Izuku’s arms again even though he isn’t. God. How long has it been since someone scented something for him?
He’s distracted from that train of thought by Izuku’s wobbly voice. “Kacchan keeps my merch?”
Katsuki peeks one eye out from underneath the hoodie to catch sight of the green scarf Izuku is holding. If only he knew.
“Ugh, like you don’t keep mine.”
There’s no getting out of that anyways. He can’t lie.
“Of course I do. Kacchan’s my favourite.”
Katsuki’s stomach rearranges itself.
The green scarf lands on top of the hoodie, and Katsuki brings it under to press to his nose. Cool again, even though it doesn’t make any sense.
Izuku comes to perch on the edge of the bed, next to Katsuki, and his hand pets at Katsuki’s hair without turning to face him.
“I didn’t find any blankets,” Izuku says, pausing. Katsuki is willing to bet money that he’s biting his lip in a nervous habit that Katsuki’s failed to beat out of him. “Does Kacchan not have any nesting material?”
Ah, fuck. Katsuki would sit up if he had it in him; instead he slumps further back into his pillow and stares at the ceiling.
Izuku turns, then, pushing the hoodie and scarf away to unhide Katsuki’s face.
“It’s okay, Kacchan.”
He needs to shut up before he makes Katsuki cry again.
“Kacchan?”
“Mm.”
“You want me to leave?”
Katsuki stills. No. No, no. That would—no. He doesn’t want to ask though.
Still a coward.
“Do what you want.”
He flinches internally as he says it.
“Okay,” Izuku says, and Katsuki turns to his side and holds himself together as Izuku’s weight leaves the bed. He can’t watch him leave.
—
Katsuki’s grown used to the sight of Izuku’s back.
It doesn’t get easier.
—
The mattress dips again.
Izuku’s body wraps around his own from behind, solid and there and not leaving.
Katsuki shivers. Izuku’s arm wraps around his stomach, hand lying on his chest, his heart, his scar. The other sneaks under Katsuki’s head. Less comfortable than a pillow, but Katsuki wouldn’t change it for the world when Izuku folds his elbow to be able to reach Katsuki’s hair and play with it.
It’s a different type of relief to be held so close. Warm, too warm, but inexplicably, Katsuki no longer minds. Izuku carries a forest with him, and there’s little Katsuki likes more than sprawling under the trees with the sun beating over his exposed skin.
Fantasy Izuku is never so present, fleeting in and out of Katsuki’s mind’s eye, his touch lighter than a feather.
This Izuku stays. He’s heavy, and his breath tickles the back of Katsuki’s neck.
—
He leaves Katsuki’s side but comes back with the stupid protein bars and sport drinks, and he stays.
—
Sometimes, it’s hard to remember why he worries.
It’s them against the world and always has been.
—
“Kacchan?”
“Hm?”
Izuku doesn’t elaborate. His lips ghost over the back of Katsuki’s neck.
Katsuki turns in his embrace to catch his eyes.
The air is thick around them, but Izuku’s alpha seems content with their closeness and nothing more, staying dormant. Katsuki is grateful because if Izuku started to touch him, Katsuki wouldn’t have it in him to make him stop.
Their knees slot together, and Katsuki squeezed Izuku’s leg between his own in reassurance. It doesn’t matter what Izuku has to say. Katsuki’s gonna match him blow for blow.
“Have you ever…” Izuku trails off, arms tightening around Katsuki, “…with anyone?”
“No,” Katsuki whispers. It’s not exactly a secret; no one’s ever asked him before.
If Izuku was less oblivious, he’d know the reason why.
“Do you not want to?” Izuku asks. “I know I come here a lot, and. I realize my scent is all over. If that’s the reason you don’t bring another alpha here then I can stop—”
“It’s not,” Katsuki cuts him off, heart lurching. His home only feels like home because Izuku’s here even when he’s not.
Izuku deflates and tugs Katsuki closer.
—
“Your fever is better.”
Katsuki blinks, taking in their position with groggy eyes. He must have fallen asleep because he doesn’t remember shifting to lie on Izuku’s chest like this.
Katsuki’s omega is at ease. For once, the quiet voice in the back of Katsuki’s head doesn’t nag him, content to be around his alpha.
His.
Katsuki’s long given up on putting a lid on the mate lingo. It’s just in the safety of his own mind.
“Kacchan?” Izuku’s hand grabs Katsuki’s. “Is it okay if I give you some things? For, um, for your nest?”
Katsuki focuses on the feel of his hand; held, caught, captive.
“Like what?”
“Just…some of my clothes and a blanket, maybe? I don’t know. Whatever you want. I want Kacchan to have it.”
A nest made up of Izuku. That would—yeah.
His throat lumps at the thought of making a proper nest. He nods into Izuku’s chest.
Izuku’s happy hum squeezes Katsuki’s heart.
Maybe Katsuki doesn’t have to ask. Maybe Izuku finally gets it.