The 'tummy tuck' is a slang term used for a shotgun maneuver used in the Xbox 360 game "Gears of War". In multiplayer it is possible to shatter an opponent with one blast of the shotgun as long as the barrel is near or practically inside the opponent's body. Because the move is done without aiming, each character will hold the weapon at their hip, positioning the barrel on the victim's stomach. The name comes from a term used in plastic surgery where unwanted fat is removed from the tummy area.
If someone tries to get you with the tummy tuck just pull out your lancer and cut their ass down.
COG1: How did I just get killed with one shot?
COG2: You got tummy tucked, fool.