A meme originated from the anime "Umineko no Naku Koro ni", in which the main character Battler attempted to solve the mystery of how people were killed by saying that "They swallowed down some small bombs which exploded inside their stomach"
It's mainly used to note that someone's argument is invalid and irrelevant to the subject
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