I want to try anilingus on my girlfriend. i know this can cause many problems. can i get a hepatitis b or a shot. can i do this with out any risk?

To minimize risk: From rimming, wash the anal area prior to the activity and consider using some sort of barrier such as latex dam or even Saran wrap. Infections transmissible from rimming include all the forms of gastroenteritis which may be viral, parasitic or bacterial. Hepatitis a can be transmitted this way but not hepatitis b.

Transmission: You can certainly get vaccinations and they are helpful in many ways, but unless your gf has these diseases they have nothing to do with analingus. This is a life-style choice. If your gf washes thoroughly and has not overt GI diseases you should be reasonably safe. You cannot do this without risk.