This generally happens when someone has been working out or stressing their torso and then a little poot comes out with an amazingly awful stench.
by AustinFera December 29, 2005
Farts the are made by trapping air in your anus. Accomplish this by relaxing your anus muscles, usaully in a bent over position, thus allowing AIR to enter your butt. Then closing your anus, and letting it rip whenever you desire to.
by SkyLuker June 29, 2008