Dental dams are made of a stretchy material such as latex or polyurethane. They come in different colours and they are usually square shaped. Dental dams can be flavoured or unflavoured and can be used with or without lube. They are used to protect people from getting a sexually transmitted infection (STI) of the mouth, throat, vulva or anus. They are used for performing oral sex on the vulva or anus of another person; the dam is placed over the vulva or anus (or both) to create a protective barrier between the mouth and genitals.