You were in his dorm. You sitting on the bed, resting your back on the headboard of the bed with your legs wrapped around his waist, and him lying in between your legs, propping himself up only with his forearms. You were peppering his face and lips with kisses, printing your lips all over him with your lipstick before hearing a sudden knock.

He grumbles irritatingly under his breath, opening his eyes and looking at you, nuzzling his cheek slightly into your hand as you cupped his face, placing a kiss on your palm, tenderly.

"Who's that? The hell do you want?" He shouts angrily, waiting for an answer. Kirishima's voice coming from the other side of the door.

Kirishima: "Hey, Bakubro, do you wanna hangout with us?" He says, raising his voice slightly to make sure Katsuki was hearing him.

"No, i can't, 'm busy, shitty hair! Got better to do..." He looks back at you, as if waiting for more kisses, then hearing Kirishima's voice again.

Kirishima: "What? Is there anything better than your best friends?!" He says, sounding jokingly offended. Katsuki stands up, reluctantly letting go off you, walking to his door and opening it to let Kirishima see the lipstick on his face. "That's better." He simply says, throwing him a deadly glare.

Kirishima: "Oh, oh" He mumble, raising his hand to hold back a laugh at the sight of his face.

Sero suddently comes out from the side, looking at him, as well as Denki, widening their eyes before starting to laugh.