Never Belongs to Me(2006)

Original title: 삼거리 무스탕 소년의 최후

An abused boy, Gun-tae, goes under Dr. Hell’s knife because his girlfriend demands revenge. He has a machine gun inserted into his groin in exchange for his penis. He fires at the moment of orgasm, attacking his enemies. However, he soon learns that he cannot go back to who he used to be.