From the English "buttocks" and Germanic "geist" = ghost.

The haunting, stretched, sort of thin, really, feeling your wife's ass has after you cum in it (magnificently) and pull out.
Sweating, back arched, face flushed, Shana felt the metallic emptiness of the buttgeist as Jack pulled out of her ass.
by Dickless May 2, 2008
Get the buttgeist mug.