Piquerism is a sexual fetish for piercing or penetrating another person's skin with sharp objects such as knives, razors, or pins. Commonly the groin, breasts, or buttocks are the targeted areas. The penetration can be damaging enough to cause severe bleeding or even death.
More About Piquerism
Much of the documentation on piquerism centers around violent criminals and mutilation of the bodies of others making it distinct from a fetish for piercing play.
The most recent notable US case involving piquerism was in 2011 shoppers in Virginia reported having their buttocks stabbed through their clothes by an unknown assailant who was referred to as "the Butt Stabber."