The act of taking a shit on somebody's tummy area and then burying one's face in it and then blowing hard, making a satisfying farting sound.
I took a shit on Fred's tummy, rubbed it in a little and then I pressed my face in it and blew real hard, making a farting sound. Fred giggled. That's what I call giving a Dirty Zerber !!
The term "zerbet" was used by Bill Cosby in his role as Dr Heathcliff Huxtable in The Cosby Show i the 1980s to describe a "raspberry", his stage daugther Rudi had given him. A "raspberry" or "zerbet" is the act of putting one's lips against a body part, principally the belly, and blowing air. A tickling senstion ensues.