It's a game. When you burp, you or your friends say "baganga". Then you have to put your thumb to your forehead and wiggle your fingers, pointed upward. If you don't, you'll get smacked on the forehead.
usually an aquatic practices teacher or math teacher, is brainless to the pointwhere it hurts, thinks he is funny but is dry, likes men but not gay, has no drip, has one child