A thumping or throbbing expressed by the female genitalia during periods of sexual arousal, response, frustration, or climax. Described by many as being similar to a heartbeat
Jaclyn: "yesterday David was over my house kissing my neck "
Rachel:" did you do anything with him "
Jaclyn: "No...i was so horny I was getting heartbeats in my vagina "
Rachel: "Vagina heartbeats!!"