You never want something until you can't have it. So, each week in The Sell-Out, we're getting the scoop from your favorite retailers on what's selling like crazy. Watch this space to find out what everyone's buying, sign up for wait lists, and keep tabs on restocks.We know it may sound crazy, but lately one-piece bathing suits are threatening to throw bikinis right out of the water — just look to Taylor Swift's entire crew or Beyoncé's recent beach day for proof. As a whole, the style is more sophisticated, versatile, comfortable, and universally flattering than an itty-bitty two-piece — but there's one option in particular that's going viral this summer.After coverage here on R29 , as well as in The New York Times, Harper's Bazaar, Vogue, and more, newly launched swim label Cocodune hit it big-time. And its most expensive swimsuit, the Director Deep V , in particular is selling like crazy; to put its popularity into perspective, the piece has been ordered and shipped to customers in all 50 states in the past 12 weeks. At $182, it may sound like a lot, but its price tag is somewhat justified: It's cut from an ultra-soft fabric that mimics silk (rather than the brand's other fabric, which is more taut and designed for performance), and its flattering silhouette has already become a must-have among bloggers and influencers. Plus, it's one of those pieces that can easily be styled on or off the sand, which means you'll likely get your money's worth.If you're not totally sold on the price, we've got good news: The discount code "DIVEIN29" will give you $20 off on bathing suits and the brand's newly launched eyewear collection. So if you're ready to take the plunge, click on to shop this best-selling style (and some similar alternatives) that will help you get through the rest of summer in one-piece.