About sex and mental health

I am not sure what your question is regarding the "mental health" aspect of your question, and would be happy to answer it with more clarification.

There are many different types of "sex acts" that some people are comfortable with, others are not. Being comfortable and wanting to experiment can change on the "mood" of the moment, the trust between each partner in the relationship, as well as many other factors.

The most important thing is that if you do experiment sexually, make sure you are wanting to experiment (being a little timid/shy is OK), are open to the idea of experimenting, and that the other person is able/willing to hear if you want to stop the experimental sex act at any time.

You may not be ready to experiment sexually with this person, if your motivation is to "keep them" so they do not find someone else. This does not sound like a mutually monogamous, trusting, respectful and healthy relationship...all of which are important aspects when deciding to willingly and joyfully experiment with sex.

As far as your specific question regarding anal-oral sex (the proper term is "anilingus", and the slang term is "rimming"), it is important to know that there are ways to practice this using safer sex techniques. Many people do choose to clean the area thoroughly with regular soap and water to remove any traces of feces, but it will not get rid of bacteria. It is important to know: "...because the interior of the anus hosts intestinal bacteria, oral-anal contact carries risk for giardia and other intestinal maladies. Using dental dams, cut condoms, and lube will greatly reduce the likelihood of transmission of STIs and other infections". You can read the entire post at: Go Ask Alice: What's Rimming? and Go Ask Alice: Anilingus and Safer Sex