Blac Chyna and Rob Kardashian are all over social media. It isn't just all fast cars, baby bumps, and emoji, either.Chyna got into the how-to business on her Instagram. The soon-to-be Mrs. Robert Kardashian posted a video with instructions on how to do a weird trick with your tongue."First, you stick out your tongue. Then, fold it two ways."Okay, that sounds simple. It also looks weird.A lot of people believe that tongue rolling (or folding, or whatever-ing) is a genetic trait that only some people carry. Not true, according to PBS Whether you can do it or not, Blac Chyna is here to help you try.