Responses
Closest thing we have to something like that is a brief flashback in Imasara Briefs, which still doesn't really explain if Maya began to like Nemu /because/ he saw him in his briefs, or if that whole incident even happened because he already liked Nemu before that.
I'd really like to go more in depth about it too ;;
Is there a oneshot or something which shows why Maya noticed Nemu in the first place?