What are dental dams?
The dental dam is a square piece of rubber that is used by dentists during oral surgery and other procedures. According to the U.S. Department of Health & Human Services, it is not a method of birth control. But it can be used to help protect people from STDs, including HIV, during oral and anal sex. It is placed over the opening to the vagina before having oral sex.
Dental dams can readily be purchased at surgical supply stores.