you would put the end that sucks onto your bong mouth piece place (this would work best with a custom bong) and the part that blow out in your mouth. Then you would light the bowl, and flip a switch to turn it in.

Hmmmm I bet i could rig a pedal that lifts a lighter up to the bowl...and if you hooked the fishtank pump switch wires onto an electrical switch/the pedal you could have a bong that lights and blows smoke into your mouth when you press the peddle!

nvm all of this ranting..I kinda go on about building stuff...