A prosthesis comprising a pancake-shaped body, a narrowed neck and a flared flattened handle sized and shaped to shield the posterior vaginal wall from frictional contact during coitus. The pancake-shaped body unfurls during insertion and provides for the prosthesis to be retained within the vagina and the flared flattened handle prevents the prosthesis from entering the vagina during insertion of the prosthesis or during coitus. This prosthesis decreases the volume of the vagina and decreases the area of the vaginal opening providing a non-surgical, cost-effective solution to tightening a woman's vagina. The posterior vaginal wall prosthesis enables women who have larger vaginas to use tampons.