Concreters Smile
A concreters smile occurs when an individual exposes the top most part of their buttocks to another presumably unsuspecting person within eye view. This has also been called a plumbers crack, or a partial mooning.
"So Billy-bob when down to pick up his burrito and next thing you know he was giving me concreters smile!"
concrete smile
forcing someone to get down and bite a curb as you stomp on the back of their neck, breaking the jaw and many teeth.
In American History X Derek Vineyard gives a black man a concrete smile for trying to steal his car.