 There is not a high risk of transmitting HIV through oral sex. There's a very low risk. If precom or semen go into your mouth, you're either swallowing it and digesting it which kills the virus or spitting it out. And if you're worried, you can use mouthwash or rinse your mouth with water a few times. Using mouthwash after oral sex does not protect you from viruses or bacteria. There's no evidence to suggest mouthwash kills viruses or bacteria. We regularly counsel people in the sexual health clinic so that they don't have this false sense of security of having unprotected sex and then trying to clear their mouth out with mouthwashers. It just doesn't work. Secondly, ingesting viruses or bacteria doesn't kill them. They grow inside our body. Saliva, gastric secretions do not kill them or digest them. Just use your common sense. People suffer from viral diarrhea. Related to adenovirus, rotavirus, we have severe diarrhea. It's a disease, an infection. So same goes for HIV. If you swallow it, it grows inside your body. It doesn't get killed. So again, use protection.