Chapter Text
It starts with dirty clothes strewn across clean sheets.
Izuku's out sick for the day and insists Katsuki still go to work instead of taking care of him. "It's a cold, nothing I can't handle," his boyfriend reassures him.
So he goes and has a shitty day dealing with all the people who keep asking why Izuku hasn't showed up. First it was Aizawa, who inquires about his absence from UA, asking him if he was okay. Then it was literally every sidekick at their agency. Someone asked about him, needing his advice, another wants to continue some chat they started another day and left disappointed. The rest just miss him or wish him well.
Whatever the reason, Katsuki is way past tired of getting reminders that his other half isn't there to stand beside him. He picks up some warm, hearty soup from one of Izuku's favorite restaurants on the way home. He might not be able to taste it, but it's got some good stuff in there and that's what matters.
But when he brings in a tray with the warm soup and some hot tea with honey, he finds Izuku curled up with a bunch of his sweatshirts and tank tops, ones he knows for a fact hadn't been washed yet. He's a little more than a little grossed out at the sight.
Izuku's eyes flutter open and he stretches out over the clothes, rubbing his face into the shirt Katsuki had worn yesterday and acts like he hadn't littered their bed with Katsuki's sweaty, stinky clothes.
Katsuki makes sure to do laundry the next day, much to the chagrin of his boyfriend.
—
The concept of Izuku rubbing on Katsuki isn't a foreign thing to him. Recently, however, things have started to change.
Katsuki is waking up from a nap when he feels the tip of Izuku's nose rubbing against his neck. His boyfriend breathes deeply, sighing at the juncture where his neck meets his shoulder. It was nice, and Katsuki thought it was leading somewhere, but Izuku pulls away. He rubs his wrist along Katsuki's arm as he rises from the bed before leaving the room, and Katsuki, who's now sporting a half chub.
A day later, they were going out on a date. Katsuki's excited because Izuku thinks they're just going out for a walk in the park, but they're really going to a museum that opened an exhibit showing the evolution of quirks. He knows his nerd of a boyfriend is going to get a kick out of taking a tour and learning what it was like when quirks were first integrated into society. The very end of the tour is supposed to have a room filled with art the museum commissioned from local artists, featuring All Might, as well as their generation of heroes. Part of him hopes to see a painting of him and Izuku in the exhibit, but he doesn't know yet.
As Katsuki gets ready, he smells his favorite scent—Izuku's cologne. It's something new that he's picked up in the past few weeks and it drives Katsuki wild every time he smells it. It's gotten to the point where Katsuki had to draw a line in the sand, telling Izuku that he cannot, by any means, wear this fragrance to work because it's too damn distracting.
Katsuki can't put a finger on what the scent is, it's just Izuku, but... more concentrated. At one point it was explained to him, but all Katsuki heard was something about pheromones.
Izuku walks in from the bathroom after spraying the cologne and Katsuki just feels all the stress leave his shoulders when he smells it on his boyfriend. It's amazing how that happens. But just like the day before, Izuku brings his wrist up to Katsuki's neck, rubbing circles into the skin.
It's a weird feeling, but he can't say that he doesn't like it. Plus he smells like Izuku, which is both an amazing feeling and will prove to be a distraction later.
"What are you doing?" Katsuki asks, his eyes boring into Izuku's as he tries to figure out the man's motives for rubbing himself all over Katsuki.
"I just want you to smell like me, that's all," Izuku smiles. There's such a sweet smile on his face that Katsuki doesn't question it anymore. It's their day so he'll humor Izuku with whatever he wants.
They have a great time at the museum, just like he expected. Despite their disguises, they're still spotted by a few fans who keep a respectful distance. Katsuki's fine as long as they stay away, but their presence only makes Izuku hold on tighter to his arm, rubbing their wrists together as they admire the large portrait of Deku and Dynamight fighting side by side—just as they should.
—
"What the hell is that?"
Katsuki had walked into their bedroom to get Izuku up for breakfast, but instead of finding him struggling to get out of bed, Izuku's already up, standing in front of their bedroom mirror.
"Kaminari left his choker here by accident. I told him I'd bring it in today," Izuku muses, stroking the accessory that wasn't supposed to be adorning his neck.
The sight pulls katsuki in and next thing he knew, he's standing behind Izuku as he gazes at his reflection in the mirror.
"Why do you have it on?" Katsuki wraps himself around his boyfriend and presses a chaste kiss on his cheek. It's a simple gesture, but the two bodies melt into one another from the comfort it brings.
"It looks like a collar, doesn't it?" Izuku's eyes are wide, pupils dilated as he stares at the simple line of black that was fastened by a silver buckle.
"What? You want a dog collar?" The words come out a bit rough, but Katsuki can't think of anything else when he looks at it. He's always thought so, even on Dunce Face, but it somehow looks less stupid on Izuku. But then again, Katsuki's always biased when it comes to the man he loves. To him, Izuku looks good in whatever makes him most comfortable, except maybe the nerdy ass t-shirts he chooses to wear all the time that Katsuki only tolerates.
Much like the one he's wearing now, that says, "stress sleep," on it. He tends to bring it around exam time when he's eager his students to succeed. Provisional licensing exams are coming up and Izuku's goal was to prepare everyone to pass on the first try.
"Not a dog collar! But..." Izuku's voice trails off and the corner of his lips turn up slightly, like he was thinking of something pleasant. Katsuki wants more than anything to know what the hell it is. After all, how is he supposed to help Izuku realize his dreams if he never speaks them into existence?
"But what?" He encourages his lover, trailing his nose down the side of Izuku's jaw until he's nudging the choker.
"I don't know what I was thinking. I just wanted to try something new."
"I think it's kinda hot," Katsuki hums into the back of the neck, feeling Izuku shiver in his hold. It is hot, and while he may not understand what's been going on in his boyfriend's head as of late, none of this new behavior necessarily ticks him off. Maybe the dirty clothes, a little, but he's never once shut anything down before Izuku could tell him what he wants.
"You do?"
"Yeah," he breathes onto the leather. Katsuki couldn't put a finger on just why it's spurring something in him, just that it is. He doesn't think he'd mind if Izuku wore something similar, just more in his style, but there is one flaw. "Covers too much, though. Can't leave marks to traumatize the brats if it's in the way."
"Kacchan!" Izuku pulls away, turning to face the taller man. His fists beat lightly on Katsuki's chest, but it's too light for someone pretending to be upset.
He can't hold in the laugh that threatens to erupt from his chest whenever Izuku gives him that look. The one that he always makes when he's pretending to be more innocent than he actually is. If only his friends knew what depraved shit comes out of his mouth when no one else is around. "What?" Katsuki smirks, which only spurs on Izuku's teacher mode.
"That's rude! And very inappropriate!" He pouts, which only makes him more adorable. Katsuki wants to bite his cheek, a place no necklace could cover.
"It wasn't intentional, but ya might want to let that waterhose brat of yours down easy. I'd be surprised if he isn't in love with you with how pissed he was that I left bites on your neck."
After Katsuki's last visit to the class as a guest teacher, he'd been cornered by the pipsqueak who dared to threaten him if he ever left another mark on his precious sensei's skin. Katsuki didn't want to look like a coward and back down, but he's cut down on the marking significantly, which apparently is something they both enjoy.
"But I like the bites," Izuku whines. He touches his mostly unmarked neck with a sigh.
There it is—there's the shit no one expects him to say. Katsuki loves it, loves Izuku, spicy thoughts and all.
"You tell him that," Katsuki grumbles, turning around to get back to the kitchen.
Izuku shouts at him as he leaves the room. "Again, inappropriate!"
When Izuku comes out of the bedroom to eat his breakfast, Katsuki notices his collar sitting up a little higher on his neck. He chuckles to himself, knowing that even if Izuku managed to cover his neck, that he'd just get marked elsewhere.
Izuku said it himself, he likes to be bitten.