A cage made of plastic, silicone, metal, or another material that fully encompasses a penis. The cage is then locked so it can't be taken off without the key. It's designed to prevent erections &
masturbation and is often used in bdsm
relationships where the key is given to someone's
significant other, called a keyholder. It is still possible to masturbate in them however, either by using a vibrator on the cage or using a dildo in the ass.