The no so common practice of body modification
by having foreign bodies of stainless steel implanted under the skin, commonly in the shape of a ring, a plate, or a star. Surgical implantation of magnets, spikes, and common household objects are also categorized this way.
Me: Crazy Johnny is in the hospital with staph infection after attempting to implant a Nintendo controller into his left arm!
You: Yeah - if you're going to go for the doucheoplasty, at least go to a professional.