They punished Bakugo and Izuku in the dorms for 4 days, they were rivals to be heroes and they fight over their issues

"Hey Deku!... I'll cook so don't get in my way"

Deku is the nickname he gave to Izuku while Izuku calls him Kacchan, he knew that Izuku had a kind personality and admires Bakugo a lot so he would like to help