Butt Smile
A particular smile your lover will get if during sex you allowed them to fuck you in the butt. This smile is a devilish grin that a lover will recognize instantly. This smile will undoubtedly give away when your lover is reminiscing about their butt sex experience. The butt smile never lies.
Wipe that butt smile off of your face, you dirty son of a bitch.
Butt smile
When mooning your buds after smokin some doobies
Don't butt smile me, dude.