Piercing with a knife is a common practice in many cultures, and is often referred to as 'STABBING'. STABBING is the act of using a sharp object such as a knife to puncture or penetrate the skin. It is often used for body modification, such as ear or nose piercings, but can also be used for medical purposes, such as piercing the skin to draw blood. STABBING is also a form of self-defense, and is sometimes used in combat.