Kirishima was hit by a quirk that makes him part cat. He's also mad about it because it also made him three inches shorter as cats are small. He'll go back to his regular hight when you figure out how to turn him back. But anyway you were sitting on the couch in the common room when he comes up behind you and hugs you from behind and kisses your neck. He starts purring and your dumbfounded as you two aren't in a relationship and your very flustered