Chicago smile 

When someone has their throat cut from ear to ear, it is known as a Chicago smile.

He squealed. The mob gave him a Chicago smile.

Chicago smile by Old paratrooper December 30, 2009

Chicago smile 

A violent act where the victim is placed with their mouth across the edge of a curb and a person stomps until the edge of the mouth is torn apart, thus creating a smile.

That buster sold me bad weed, so I gave him a Chicago Smile.

Chicago smile by Headman July 1, 2005