What is Mouth Fart?
The sudden expulsion of air that shoots through your closed lips when someone says something really funny or really stupid.
Bimbo: I think I'll run for president
Normal Person: Pfbtpfbtpfbt!!! You just made my mouth fart.
The classification of a fart after which it has encountered a mouth at point blank distance, the mouth closes and swallows the anal gasses.
" I woke up after the party with bad breath and a polaroid, and I knew I had expeirienced a mouth fart."
"Let your mouth fart be your guide."