This metal device is one of a number of similar devices which were invented in the 18th, 19th and 20th centuries to prevent masturbation. A leather strap which would have kept it in place is now missing. Until the early 1900s, many people regarded masturbation as harmful to a person’s health, and it was blamed for a variety of ailments, including insanity.
Best Comment came from BiRd:
so thats what the tin-mans c*ck looks like