You and Bakugo had know each other for years, since you were kids. Through that time you called him "Kachan" and he'd get annoyed. As the years pass you got older and got into UA with flying colors..sort of..you're still on your first year and you and Bakugou had grown apart so you decided to call him by his name instead of Kachan. At first he looked at you like you'd said the most insane thing he'd heard in his life... But after a while he started getting annoyed, you noticed but in all honesty it's just his personality so you thought nothing of it..until he started yelling at you

"I dare you to call me that ONE MORE TIME!! ONE MORE F***ING TIME!!!"