Izuku jumped when a hand slammed the shut locker beside his own. The sound echoed in the quiet room, a bang that clattered like his heart against his ribs. His hands froze on his tie, that he'd gotten as far as to slip around his neck, but not actually tie yet. Slowly, he turned around to give his full attention to Katsuki.

His classmate loomed over him, red eyes narrowed, snapping with fire the way his palms weren't. Yet anyway. "Deku," he asked, his voice low. "What the fuck do you think you were doing?"

Izuku blinked. Giving an automatic smile, he said, "Changing?"

Katsuki's free hand grabs a fistfull of the front of Izuku's shirt. He shoves him back against his locker. Izuku reflexively reaches back to brace himself with one hand while his other one pressed flat against Katsuki's chest. "Changing," Katsuki sneered, lip pulled back as he mocks, "You were just changing.Well, then, I suppose it's perfectly fine for you to be ogling some guy's ass while you're changing."

"I wasn't-" Izuku started but went quiet as Katsuki further invaded his personal space by leaning in so close his hot breath stirred against Izuku's lips. "K-Kacchan-"

"You're mine, Deku," Katsuki said, staring him straight in the eyes. "And I don't like what is mine to stare at the ass of fuckers like fucking Halfie."

Oh. Izuku blinked. Katsuki was jealous. Shouto was usually the one who on the opposite side of the bench from Izuku, so whenever he turned that way he usually noticed his friend. He hadn't thought much of it, of course. Shouto was his friend. Katsuki was his boyfriend. There was a pretty big difference there. One of them being that things like this worked on Katsuki.

Izuku glanced down. His cheeks flushed pink as he mumbled, "I wouldn't bother looking at him while I changed if I could see you instead, Kacchan."

After a moment of silence from Katsuki, Izuku glanced up through his lashes at him. Katsuki's face was a lovely shade of pink. Izuku's heart melted at the sight and he couldn't help but smile.

"Fucker," Katsuki said, seeing that smile. He closed the meager distance between them until they were hip to hip. "You little shit." His fingers twisted in Izuku's tie, dragging his head in. "Do you fucking get off on this shit?"

"Get off on what?" Izuku asked, as though he didn't know what Katsuki meant. He didn't stop smiling. He let his hands carefully, slowly, reach down and settle on Katsuki's waist.

"Pervert," Katsuki whispered. His face was red. Izuku lifted his chin just enough to place the lightest of kisses on Katsuki's mouth. "What would everyone say if they knew you fucking provoked me to manhandle you on fucking purpose."

Izuku knew what they would say. Probably the same thing that Ochako had said when he'd told her that he and Katsuki were dating when they'd started their third year. She'd tried to stop that for a month, though it was in vain. Instead of answering, he kissed Katsuki again.

Katsuki returned the kiss this time. It was hot as his gaze and involved more teeth in the first few seconds than lips. Izuku moaned as Katsuki dug his teeth into his bottom lip, pulling it roughly before sucking. Izuku's eyes fluttered shut as they kissed. His fingers crawled up Katsuki's sides, slipping under the jacket of his uniform, following muscle and ribs all the way up.

Just as he'd managed to coerce Katsuki to give up his tongue for Izuku to suck on, Katsuki pulled back a full step. Izuku shivered at the sudden loss of body warmth. "Kacchan?" He tried to pull him closer again, but Katsuki's hands held him back.

They jerked suddenly, tightening Izuku's tie into place. Izuku blinked and then looked down to see Katsuki had tied his tie perfectly straight, instead of the shortened version he preferred. "Eh?"

Katsuki smirked as he held up a finger, "Here's some free dating advice, nerd. One: Don't look at anyone else but me." Adding a second, he said, "Two: Don't fucking provoke me at school, shithead, or next time I'll make sure that half hard cock of yours is a full fucking fledged boner you have to deal with."

Izuku opened his mouth to argue but stopped before he did. Maybe looking at Shouto had been an accident, but the rest of it? Well. Katsuki gave kisses like a drowning man seeking air whenever he was jealous. Could he really blame Izuku for wanting to be kissed like that all the time?

Apparently, yes. Yes he could.

Smug as a well fed cat, Katsuki strutted out of the locker room. Izuku frowned down at his perfectly straightened tie and muttered, "If you can tie a tie, why don't you ever wear one, Kacchan." Really, his boyfriend was the most ridiculous.