In this AU, you're both cats.

Katsuki and you both lived in a modern apartment with your owner, who was barely ever home, leaving you both alone almost everyday. It was Friday, and they were out partying, so you were both sitting bored at home. You two had the slightest bit of chemistry, and would show your love through licks and tongue sharing. But this time, his usually gentle kicks were different. You were laying in your little bed, curled up with your tail wrapped around you, when he appeared through the door. He was decently taller than you, so he towered over you with ease. He padded over to you, and started to lick around your neck and legs with his rough tongue, a sign in cat language that said. . He wanted kittens.