A forced, fake-looking smile you put on when you have to pretend you're enjoying something awful, like kissing your boss's ass. Counterpart to a shit eating grin, where you put on a big stupid smile, completely unaware of an uncomfortable situation you've created.
Bob told that dumbass Michael his presentation was great. You could see the ass eating grin plastered on his face.
by kickflipthecat July 27, 2010
Get the Ass eating grinmug.