This is a distortion of an old expression: "adding insult to injury". The original meaning was that it's bad enough to be physically injured by someone, without receiving a verbalinsult from the assailant as well.
"As if getting my parked car hit by a truck wasn't bad enough, the car being towed away by the parking police was just adding injury to insult."
Boys who enjoy yaoi (a genre in Japan that contains sexual and/or romantic relations between two men); literally translates to "rotten boy"; corresponding female : fujoshi