Vaginal chafing is typically caused by the same things that cause it in between the legs or under the boobs: sweat and friction. “The primary problem is irritation from the skin rubbing back and forth against itself, and it gets worse in the heat when we’re sweating,” says Karen Duncan , MD, OB/GYN, an assistant professor at New York University Langone Health. It can be exacerbated by shaving , wearing tight panties, or wearing shorts with built-in underwear that digs into your skin.It can also occur if you're having an intense sex or masturbation session , that involves prolonged, painful rubbing of the area.Usually chafing just causes redness and a stinging feeling, but if it’s severe it can lead to swelling, bleeding, and infection, Dr. Duncan notes.