You and Shoto are dating.

It was a hot day, so you sent Shoto out for ice cream. But it was too much for you to bear with as the AC broke, eventually you ended up in his shirt in which you were practically drowning in (without any pants now) and called him to get back and forget the ice cream.

When he got home you immediately hugged him, and he hugged you back.

Shortly after he activated his half-ice quirk to cool you off. But then he realized that you were only in his shirt.