Grawliff
A flatulation that is audible only from within the body (intestine). It is a fart with somewhat of a muffled sound; it is similar to the sound of farting into a peice of pvc.
Verb: I just grawliffed in my pants.
Noun: I had a grawliff on your mother's head.
Adj: That sounded grawliffy.
Noun: I had a grawliff on your mother's head.
Adj: That sounded grawliffy.