A friend of mine, who happens to be Filipino, told me about the goat eyelid sex toy. Apparently, the more rural areas of the Philippines raise goats, and it is common practise, upon slaughtering a goat, to carve out the eyelids in a circle completely around the eye. This eyelid is tied around the penis to restrict circulation, causing the penis to stay erect longer. At the same time, the eyelashes provide a tickling sensation for the female clitoris.
The goat eyelid, or "happy ring" was first used as a sex toy in Tibet during the 13th century. A cycle of drying and steaming the eyelids was used, to season the eyelid into a leathery, longer-lasting state.
However, my friend was distressed to report his goat eyelid eventually wore out. He blamed this on his failure to soak the eyelid after use.