Here's a recipe for you: take a bottle or jar, whatever you have on hand, just some type of container taller than it is wide. Now defecate into it. That's right, just go right on ahead and poop in there. Go ahead and take a leak while you're at it. You'll want it mostly full, but not all the way -- plenty of waste in there, but with some space left at the top. Now stretch a balloon over it, set it aside in the sun somewhere, and wait for it to ferment. The balloon will fill with the gasses produced from the fermentation. When there's enough gas in the balloon for a good lungful, remove it -- careful, wouldn't want to lose any -- and huff it.
Congratulations. You have just produced and inhaled jenkem (or jekem), a drug that has apparently been in use among African youth since the mid-90s and, more recently, has been gaining a foothold with U.S. teens, though many authorities, including snopes, claim the drug to be a hoax.
Alternatively called "Leeroy Jenkems," "butt-hash," "winnie," and "runners," jenkem has also been called "shit," though that isn't even a street name; it's just ingredients. It has also been called "disgusting." It is reputed to have hallucinogenic properties, producing aural and visual hallucinations in users; a test of hydrogen sulfide "sewer gas" on mice in 2006 revealed that gasses like those produced by jenkem could result in hypoxia, a lack of oxygen which can be euphoric, but potentially dangerous.
Hoax or not, jenkem is almost universally regarded as highly distasteful. Remember: friends don't let friends huff butts.