When something is so gay (here meaning 'awful') that it cannot be defined in terms of anything other than the most awful thing to happen to literature this century.
Most often applied to books, bookish people or book-related things.
Louise: Did you read that poem Martin sent you?
Una: Yeah, it was 50 shades of gay.
One of my personal favorites! When we the guards decide we've had enough of one "homeboy's" shit and bust into his cell looking for contraband that may or may not be there. Somehow it always turns up!
they havin' a shake down in Big Daddy's cell. Boss Cain gonna be givin' it to em now!! He don't fool around!