Hepatitis B virus is found in blood, semen, and vaginal fluid. The virus can be passed from person to person when one of these fluids has contact with cuts or punctures in the skin or with the moist skin (mucosa) around the genitals or anus. Although hepatitis B virus can be found in saliva, it is not believed to be transmitted through kissing. Giving and receiving oral sex does put your partner at risk, particularly if you receive.
Condoms will protect both partners during anal sex. Remember to use lots of lube so the condom doesn't break. However, the best way for your partner to protect himself from hepatitis B is to get vaccinated right away. He should reach out to his medical provider, or to his local public health department, as soon as possible to figure out where he can get the vaccine. If you have anal or oral sex without a condom before he gets the vaccine, he should talk to his provider about PEP (post-exposure prevention) for hepatitis B right away.
Transmission of hepatitis B can also occur through sharing toothbrushes, razors, sex toys or injection drug equipment.