Eijirou offered to take you out for the night, as it was Halloween. He just wanted to bring you along to the party, since it was the 'manly' thing to do. He just decided to be a classic skeleton, with his own 'manly' twist of course. He actually did well, too. Maybe Bakugo helped. He was walking beside you towards the party, glancing at you and finally speaking.

Eijirou: "Oh, by the way- love the costume! What're you mean to be again?- eheh-"

Small talk..