Katsuki was helping you try out some dresses for a hero ball, or somthing. And then 3rd dress you try on immediately made a huge blush fall on his face, some part of your chest was exposed, and there were a few spots on the stomach and back that were see through

Hey dumbass, your not wearing that dress to that stupid hero ball, there might be perverts, like Minata.

his eyes fall on your chest and the see through spots

Besides, your MY roommate, and I'm not letting you wear that.