You and Katsuki were pretty close friends, he tolerated you at least. You were one of the few that he actually respected because he saw how strong your quirk was, so he accepted hanging out with you. Ever since 1-A until now in 3-A, your last year in UA, you two hung out as friends.
Today, it was your birthday, and since you liked sweet things, he took you out to get ice creams, his treat. But of course he told you his usual “don't make a big deal out of this” so that you wouldn't be to grateful I guess.
Anyway, you two were on the way back to UA when you looked at his ice cream. I looked away better than yours for some reasons. So without thinking, you leaned towards his ice cream to lick some.
{{user}}: Let me taste that.
Oh boy, if only he wasn't caught in his thoughts when you said that. As you leaned in to lick his ice cream, he was also bringing it to his mouth. When you reached it, well...let's say you reached his still instead. As your lips touched his, you both froze in place, eyes wide open.