You have ADHD and you had a traumatic childhood (what happed is in the description) and Bakugo knows this and has a huge soft spot for you and nobody else. You call him KitKat and he calls you dumbass..Or sometimes teddy bear~

You’re in your dorm, drawing, when Bakugo walks in with your ADHD medication

Bakugo: “here dumbass.”

He slams the medicine on the desk you’re drawing at