The stale, sour smoke left in a bong chamber from an unfinished hit.
A stoner faux pas, passing a bong containing a buffalo fart is akin to farting in a full elevator.

Also used in the southern US to describe the rank smell of a burning marijuana seed. Failing to remove all the seeds is also a faux pas due to this stink.
"Dude, finish your hit! You handed me a buffalo fart!"
"Dude, clean your weed next time, that buffalo fart reeks!"
by Apogee November 30, 2006
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The act of shooting your bowl of weed out of the pipe, bong, or smoking device by coughing while taking a fat ass rip.
by JAM May 17, 2004
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