post #2644511 post #3050641 post #2298292

A gusset is a pouch or extra layer of fabric sewn into the underside of some (usually female) garments, commonly seen on panties, pantyhose, tights, leggings, and yoga pants. It is usually made of cotton, and is typically included on garments made of synthetic materials. Its purpose is to protect the wearer's vagina against bacterial and yeast infections as the cotton creates a more breathable surface than synthetic materials, and to protect the vulva against friction. It is also used to provide extra breadth to the crotch seam on garments such as tights, as that seam is particularly prone to damage caused by stretching. It can usually be identified by a horizontal seam on the underside of the garment, or in the case of translucent garments, a darkened area covering the genital region.

While gussets are added to many different types of clothing, they seem to rarely appear in artwork except on panties, as they are often a notable feature to panty fetishists.

More info: https://en.wikipedia.org/wiki/Gusset