A 90-year-old man on hormonal treatment for invasive (T4) adenocarcinoma of the prostate presented as an emergency with a paraphimosis secondary to placement of four circumferential key rings around his penis. He had experienced referred penile pain from his prostate cancer, and to overcome this, had attempted to 'gate out' his pain by constricting his penis and thus stimulating the pudendal nerve. His treatment in our unit consisted of a penile local anaesthetic block, removal of the key rings with a ring cutter and manual reduction of the paraphimosis.