Actress Aya Cash posted a really telling picture that illustrates the difference between what she wears for a cable versus network television sex scene. On the left is what Cash would "wear" while filming a sex scene for her cable television show You're the Worst on FX, and on the right, Cash models what she wore while filming a sex scene for the now-canceled FOX show Traffic Light. One is a lot more fabric than the other.
Cable sex scenes vs network sex scenes. Modesty cover comparison.
So basically the one on the right looks like something that wouldn't even break a High School dress code while the thing on the left looks sort of like one of those thong panty liners or maybe a weirdly shaped Band-Aid. What that tiny strip of fabric actually is is a "strapless g-string." Essentially it's a big triangular sticker that you attach to your lady parts, and the little heart shaped piece is a butthole cover. Sounds comfy.
Even though most people would loath having to wear the weird sticky bookmark over their lady-bits, Cash told Entertainment Weekly in an interview last year that filming sex scenes isn't as uncomfortable as you'd think.
It’s not anyone’s favorite thing to do, but they make it very comfortable, and you write s– on your pasties, and you do stupid stuff to lighten the mood, and then everyone acts like a professional.