When the fart doesn't extend outside of the underwear, and when underwear is took off, there is a smell, the smell of the assfog.
Person 1: I just farted, smell this!
*Takes off underwear*
Person 2: Get that assfog smell outa here!
*Takes off underwear*
Person 2: Get that assfog smell outa here!
by Huntergohard February 4, 2013
A, real shitty word if you ask me...some say it means when you blow a fart the green cloud that results
by Anonymous July 30, 2003