Oral dams What is an oral dam? An oral dam is a latex barrier that goes over the vulva or anus for oral sex. How do you use an oral dam? 1. Check the expiration date and open the package. 2. Unfold the dam and look for damage. 3. Lay the oral dam across vulva or anus 4. After oral sex throw the oral dam away in a garbage with a lid. Making your own oral dam Sometimes oral dams can be difficult to find, but there are a couple of different ways to make them using, a condom, here’s one: Open the external condom and remove from package. Make a small cut in the rim. Unroll the condom to make a rectangular piece of latex.