Ladies, we’ve got a PSA for you. It’s about something that we know you’ve totally been wondering about for quite a while. And truthfully, our mind is blown.

Have you ever noticed a little pocket in the crotch area of your underwear? You know, the one that’s the same color and fabric as your underwear, but it forms a little flap at the part where your vagina sits. Ever wonder about it?

Well, it has a purpose. And no, in case anyone was wondering, it’s not for the purpose of shoving extra toilet paper in case there’s none on the roll next time you’re in the bathroom (not that we’ve ever done that…).

If you don’t know what pocket we’re talking about, head to your underwear drawer right now and take a look at some of your panties. We can almost guarantee that most of the pairs of underwear in there will have a little flap right at the bottom where your, achem, lady parts go.

This pocket—which actually isn’t even a pocket at all—has a name, and it’s called a “gusset.” Some people also refer to it as a “crotch lining,” but for the sake of our appetites, we’re going to keep calling it a gusset.

A gusset is defined as “a triangular or rhomboidal piece of fabric inserted into a seam to add breadth or reduce stress from tight-fitting clothing.”

In other words, it’s a little piece of extra fabric added to underwear to allow your nether region to breathe and protect it from any harm.