A b'doozy occurs when anal sex is being performed and the recipient releases flatulence resulting in the vibration of the phallic organ. See also, Oopsie-b'doozy.
b'doozy comes from the word "doozie," as in the case of the release of a large fart and someone in the immediate vacinity proclaims, "That was a doozie." However, in the case of a b'doozy, the person who would normally proclaim the previous statement is occupying the farter's butt, hence the "b" in b'doozy. "Jane gave me a b'doozy and now I need to take a shower.
by Fred Morris November 26, 2007