When a girl is hanging upside down thinking you are about to insert your penis in her mouth you pull a 180 and then rip some serious ass right in her mouth. The hanging upside down is the possum and the fart effect is the squeakyness.
My girl friend was in for a real treat when instead of giving me head I gave her the suprising squeaky possum.
by Chew-ay November 7, 2006