This occurs when a rookie bong user proceeds to wrap their lips over the top of a bong as if they were about to perform fellatio. Witnesses usually express laughter, and disgust.
Steve to Stacey - "Hey Stacey, stop blowin the bong, it's NOT your boyfriends penis!"
Fred to Steve - "Is Stacey givin Bong Jobs again? I thought I told her not to."