Japanese men are having pearls inserted under the skin of their penises, evidently to give that "ribbed for your pleasure" sensation to their partners.
I know you all think of me as a major perv. And what other people do with their own bodies is OK by me. But personally, I wouldn't do it.
After all, these are the same people who gaves us the Mighty Morphing Power Rangers, tentacle sex, and singing toilets.