Oral and Anal Sex Risks
It has now been well proven that oral sex is a potential means by which HIV can be transmitted.
And it's not only HIV -- certainly any of the other sexually transmitted diseases can be passed through oral-genital contact.
Anal sex is one of the most effective ways to transmit an STD. The receptive partner has the highest risk of contracting the disease. HIV, Hepatitis C and all other STDs can also be transmitted this way. And don't forget the wart virus. Most people aren't aware that being exposed to the wart virus and the human papiloma virus (HPV) by contact with the anal region seems to increase the risk for anal cancer.
How can you protect yourself? Avoiding these behaviors or using a latex barrier seems to be the most appropriate way.
I must say that I'm really quite bewildered by the preoccupation of anal sex and all the questions I get about it these days. I don't know if the pornographic industry has somehow raised awareness of this activity, or if this is some sort of an aggressive act that men are looking to perpetrate against women.
Certainly both partners must be willing to do this. Care needs to be taken to not damage the women's anal sphincter or rectum, as this is a part of the body that can be injured. If the woman is not interested in this behavior she should not feel as though she is letting her partner down if she doesn't engage in it. If this is not something you want to do you should not be doing it.