Many teenagers know that using condoms during vaginal and anal sex reduces the risk of pregnancy and sexually transmitted infections (STIs). But what about oral sex?

Oral sex can't cause pregnancy, and it's very low risk for HIV. But unprotected oral sex is high risk for other, less dangerous STIs, including cytomegalovirus (CMV), gonorrhea, hepatitis B, herpes, and syphilis. The good news is that there are ways to make oral sex safer.

The Basics

Many STIs are spread through contact with body fluids, especially

  • ejaculate ("cum")
  • pre-ejaculate ("pre-cum")
  • blood
  • vaginal fluids
  • discharge from sores caused by STIs

Some are spread through skin-to-skin contact.

People can reduce their risk of infection by keeping their partner's body fluids out of their vagina, anus, and mouth. Partners can use barriers during oral sex that prevent them from exchanging body fluids and reduce the area of skin to skin contact.

One type of oral sex is fellatio (also known as a "blowjob"), which is using the mouth to stimulate the penis. Partners can reduce their risk of infection by using a condom to cover the penis.

Another type of oral sex is cunnilingus, which is using the mouth to stimulate the vulva. A third type is analingus, which is using the mouth to stimulate the anus. This is sometimes called "rimming." For these two types of oral sex, partners can reduce their risk of infection by using a latex barrier between the mouth and the vulva or anus.

The Lowdown on Dams

There are a few types of barriers that people use to reduce their risk of infection during oral sex on the vulva or anus.

A Sheer Glyde dam is a thin piece of latex that is 10 inches long and six inches wide. Sheer Glyde dams were developed specifically to be used for safer oral sex.

Dental dams are similar to Sheer Glyde dams. They are small, thin squares of latex that come in the different colors and flavors. They are called "dental dams" because they are made for dentists to use during dental procedures.

Cut-open condoms can also be used as barriers for oral sex on the vulva or anus. To make a condom into a dam, unroll an unlubricated condom, cut off the tip, and then cut down one side to make the condom into a rectangle shape.

In a pinch, some people will also use plastic wrap to cover the vulva or anus to reduce the risk of infection.

Covering Up

To use a dam, lay it flat over the entire vulva — covering both the vaginal opening and the clitoris — or place it over the anus. Hold the edges of the dam in place while performing oral sex.

Here are some more tips for using dams correctly:

  • Use only one side of the dam. Keep track of which side of the dam has touched the mouth and which side has touched the vulva or anus. This will prevent partners from sharing body fluids.
  • Don't share dams with a partner — each person should use her or his own dam.
  • Use a dam only once, and then throw it away.
  • Always use a new dam if you switch from performing oral sex on the anus to performing oral sex on the vulva.
  • Some people will place a small amount of lubricant on the side of the dam that touches the vulva or anus. It's important to only use water- or silicone-based lubricants — oil-based lubricants like Vaseline or body lotion can break down latex.
  • High heat and direct sunlight can also break down latex, so store dams in a cool, dark place.

Give a Dam!

Dams are available at many Planned Parenthood health centers. Some county health centers and public schools give them out for free. Some drugstores carry dams, and some people order them online.

For more information on reducing the risk of infection from oral sex and other kinds of sex play, check out Safer Sex 101.