The art of the curb smile usually requires two people. One to pry open the victims jaws and hold them open over the curb; and the other to stomp as hard as possible on the victims head.
Curb Kid 1: Hello, Thomas, would you enjoy some curb drank?
Thomas: Why yes Curb Kid 1 i would enjoy it.
*they drink the beverage
Thomas: my mouth just jizzed
Curb Kid 1: hahaha... that IS what gazzelles do at picnics!
Thomas: you queer boy?? (redneck accent)
Curb Kid 1: is a babies sweater brown?
Thomas: maybe?
Curb kid 1: exactly...
To prop someone's open mouth against a concrete curb and then to stomp on the back of his head. The outcome will require a trip to the dentist for a set of dentures, to say the least. Thought to have originated from usage among street gang toughs.
The leader of the Jets gave his beaten opponent the coup degrace, a curb sandwich.