lol @ all this macgyver shit. good stuff. just make a regular vaccuum style grav. all you need is a bottle, a makeshift bowl (foil) and a bucket of water. cut the bottom off the bottle and when you put it in water right side up and move it up and down you are creating a vaccuum at the mouth. move the bottle up and air gets sucked down, push it down and air gets forced out. just attatch a removeable bowl when the bottle is down, then light it while slowly moving the bottle up. you can get as large or as small of a hit as you want, and you don't waste precious lung capacity just filling the chamber. bonus is you can push down on the bottle while inhaling and actually "propel" the smoke into the lungs harder than a plain ol' inhale. not for lightweights.