A sexual toy that is inserted into the anus...preferably "vibrating". Often available with a "safety tether".
As I walked away from the mirror I found that my butt egg had become disengaged due to its safety tether.
by mto April 4, 2007
Get the butt eggmug. by Marshall Law November 12, 2004
Get the Butt-eggmug. A particularly awful smelling fart from deep within the bowels. It has the distinct sulfur odor usually associated with rotten eggs.
by moraleboatanchor August 15, 2012
Get the egg buttmug. 