A slang term for Sugar-Free Haribo Gummy Bears. This expression originates due to the intense and explosive laxative effect that this product has on your digestive system.
John: "Bill why does the bathroom look like Helen Keller was playing with brown colored spray paint?"
Bill: "Because I ate 15 Bummy Bears."
John: "Fair enough."
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