Yes, it is possible for either partner to become infected with HIV through performing or receiving oral sex. While no one knows exactly what the degree of risk is, evidence suggests that the risk is less than that of unprotected anal or vaginal sex.
Studies have shown that latex condoms are very effective, though not perfect, in preventing HIV transmission when used correctly and consistently. If either partner is allergic to latex, plastic (polyurethane) condoms for either the male or female can be used.
If your partner is female, use a latex barrier (such as a natural rubber latex sheet, a dental dam, or a cut-open condom that makes a square) between your mouth and the vagina. A latex barrier such as a dental dam reduces the risk of blood or vaginal fluids entering your mouth. Plastic food wrap also can be used as a barrier.