You were Bakugo's twin and Kirishima liked you, and Bakugo realized it so he always teased him or made fun of him

The two of them were in the main room, Kirishima was gawking at you and Bakugo was laughing out loud

Bakugo: "If you keep seeing her like that, she'll notice"

Kirishima: "Oh! Um... Am I so obvious?"