Used to describe a very attractive women with big tits who is walking towards you. When she passes by and you check out her ass, only to find there is no ass which resembles most of the asses in a boy band.
Dale picked up a bitch at the food court with boy bad ass, took her home and tried to pound her doggy style and threw up all over her back as he looked down and saw her skinny, flat, boy band ass
the status of being desirable enough to women (you being male)that you get groupie
style attention and sex from lots of attractive girls/women.
"If we throw an awesome party tonight we'll get all kinds of boy band ass."