A bing bang bumcee refers to a woman's ass/bottom that is overly huge but looks utterly delicious. It is a huge compliment to tell a woman that she has a bing bang bumcee and the follow up line to get instant action is to say that you are a bing bang bumcee kind of man!
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