This is an activity done by people when they are "gettin stupid" or "gettin dumb" where a person gets so retarded that he takes a hammer and hits himself in the testicles. Bopping the bag is often discussed, but rarely done due to its obvious danger and the pain involved. It is most associated with hip-hop fans, particularly those who associate themselves with the hyphy scene. Bopping the bag is essentially the the big brother to activities such as ghostridin the whip or gas brake dippin. Women can bop their tits if they so choose, as they have no bag to bop.
we wuz gettin mad retarded up in dis mothafucka an Pooky got so stupid dat he starting boppin his bag. I said, "goddamn mothafucka you is bopping your bag!"
get mad stupid up in dis bitch an bog ya bag nadamsayin?