A large jug with the bottom sawed off, usually with a steak knife, and a cap burned out and a socket jammed in it. You would then place that structure in a bucket full of water. Next, proceed to put marijuana in the socket and blaze it up. Gently pull up on the jug structure until it is full of smoke. Lastly unscrew the cap and push down on the jug and instantly you will be blazed.
HP hits more g-bongs than anyone on the planet
1. Usually used to desribe a gravity bong.
"Yo man, lets hit the g-bong before we go to work"