I made this other one that was a terrible idea. I took one of those small gas masks that you often see at headshops hooked to bongs. I had hooked one up to a bong long before I ever saw it in a headshop and Im convinced they stole my idea, but thats besides the point. The mini-plastic bong I have turns into a steam roller if you take off the bottom plug. I plugged the top into the gas mask, took off the bottom plug and strapped one of those turbocharger looking air mattress pumps into the bottom. BAD IDEA. It popped my ears and the pressure killed my head, my nose ears eyes burned etc. I did however get EXTREMELEY BAKED. I dont reccomend it though, it was kinda painful.