Although oral sex is less risky than anal or vaginal sex, it is possible to get HIV by performing oral sex on an HIV-infected partner. HIV transmission could potentially occur if blood, pre-ejaculation fluid, semen, or vaginal fluids enter open sores or cuts in or around the mouth, such as those caused by canker sores or blisters, vigorous teeth brushing or flossing, or some form of trauma. Using a latex barrier, like a condom or dental dam, reduces your risk of HIV infection.