A company in Tokyo called BoDivas just started selling a new type of jewelry called Beachtails . . . which are charms that you attach to the crotch of your bikini so they dangle down between your legs. They sell for around $20 and the company says they're, quote, "classy." Well if they say it, it must be true.
You can . . . and should . . . buy them on Amazon by searching for "Beachtail."