Butt fumes 

A Fart

I need to go outside to expel my Butt Fumes

Butt fumes by Dollarbill1985 July 15, 2010

buttfumes 

stuff that comes out your ass. Almost always used in conjunction with fartgas. Buttfumes are always expelled and never erupted unless following fartgas in sentence.

I erupted fartgas and buttfumes.
I expelled buttfumes.

buttfumes by lightyeersaway April 14, 2010