When you are banging your girlfriend and you shove a pickle up her ass for added pleasure. After you are done, she eats the pickle. (Because the pickle is green, it is like a Martian penis, like the Great Gazoo of Flinstones fame might have.)
Katie said that she had mixed emotions about the Great Gazoo. The pickle up the ass was actually thrilling, but the pickle tasted like shit afterwards.
derived from a mistaken pronunciation of the last name "Gazo" which developed into the nickname of superb hockey player in Grand Valley, Ontario named Nik Gazo
"Another great performance by the Great Gazoo"