You might want to start doing some crunches.

Because this summer, the fashion savvy are becoming hip to what Hindu brides have known for centuries: Jewels for the body — especially the belly — are the ultimate in sexy chic. 

Maybe we've finally ditched the fish line from illusion necklaces and opted to stick the diamond directly on the skin. Or maybe the latest hot jeans, complete with sheared-off waistband (see Mariah Carey or Lil' Kim for inspiration) have brought the eyes to focus on the belly. 

"The most modern way to decorate yourself," Harper's Bazaar Beauty Director Christine Shea told the Fox News Channel, "is to bring it towards your belly."

Whatever the motivation, body jewelry proves that this summer all that glitters is skin. And at a time when the holey ozone layer has made sunbathing nearly lethal, the glimmering flints of glass, gold and glitter couldn't have arrived a moment too soon. 

Crystal Clear Fashion 

So how to get the look? It may be crystal clear: Swarovski stick-on crystal tattoos have been popping up on celebrities from actress Jennifer Love Hewitt to model Elizabeth Hurley. The midriff and the belly button (a la Halle Berry) both beg for crystalline accents. 

The crystals come in eight different designs (including swirls, stars and flowers) and rows of the self-adhesive crystals allow the wearer to go wild. And if you've been caught up in logo frenzy, you can take a cue from the latest Chanel runway shows and form the crystals into the ubiquitous double-C symbol. 

Crystal tattoos will even be making an appearance at the beach. Melissa Carden of Swarovski told Fox News Channel that "you wouldn't usually wear jewelry with a bathing suit, but you can wear a crystal tattoo." And they last and last! After a recent weekend spent at the beach, in and out of the water, the crystals remained in place. They can be used up to three times; if their adhesive weakens, Swarovski suggests using eyelash glue. 

A Novel Navel 

A few years ago, forehead bindis (that little bit of gold sparkle and colorful felt placed between the eyebrows) were all the rage thanks to No Doubt frontwoman Gwen Stefani. Now bindis are sliding down to land around the belly button as well as adorning the midriff. Diamond Bindi makes gold and pearl bindis that come in circles that lay perfectly around the navel. Their publicist, Anne Moratto, explains the trend: "It follows the trend of the midriff baring. It's another erogenous zone that hasn't been fully explored." 

Bindis can come with their own adhesive and directions but a few simple rules apply: Start with clean, dry, oil-free skin and allow the glue to set before jaunting out into the humid night air. If you have sensitive skin, you might want to test drive a bindi before a night of clubbing until dawn. When the glue is gone, you can use eyelash adhesive to keep that navel adorned! 

Belly Stencils 

Borrowing again from the Hindu tradition are henna kits from Skin Mart or the easier pre-designed decals from Ancient Mehndi Designs, which offers strips to create intricate henna designs. Henna-stenciled hands and feet have been in for a few years, but just recently have made the move to the body. 

Steal the look from the pages of June's Harper's Bazaar and add panache to your bikini with a henna design around your waist. These decals will remind you of the Cracker Jack variety as they work with moisture and will last for up to seven days or until you remove them with rubbing alcohol, baby oil or adhesive tape. More adroit souls can mix the henna themselves and create unique designs or brush the henna over a stencil design. (Henna stencils are available at many drugstores.) 

Chain of Command 

This season, "skin is definitely in," Bazaar's Shea told Fox News Channel. "If there is a perfect season to wear a belly chain then this is it." And Lori Levin, of Manhattan's body jewelry shop New York Adorned, says that they sell one-of-a-kind jewelry including belly chains, which "definitely have gotten more popular." 

"They can be really cute," Bazaar's Christine Shea told Fox News Channel, but only if you make sure the chain really fits. "It should be hanging pretty loosely on your skin," she cautioned. "It should not leave any kind of impression on your skin." 

If the chains you find commercially available are too short to fit comfortably, go to a shop that sells chains by the yard and make your own. 

Finally, with body jewelry, more is not necessarily better. Shea also told the Fox News Channel: "I wouldn't be doing all three at once, that's for sure: Henna plus belly chain plus rhinestone tattoo is a don't, definitely." Use a little restraint and you'll shimmer and shine your way through the long, hot summer ahead.