Interesting fact about this topic. There are precious too few facts! No one studies this. No one has published any real information or data I can find. I have looked. I continue to look.

Yes, STD's, Parasites, eColi, and Helicobacter as well as other organisms can indeed exist in fecal matter, but in a "clean" anus...with no visible fecal material, what would be the "bacterial load" from exposure? Cannot find an answer.

Likewise, and more critically, if you have to "bonded" partners and both are free of disease, practice good hygiene and have "empty rectums" prior to anal play, what is the risk? Great question.

Take it further. Many people engage in anal licking and kissing. Does that really diminish the "risk" as opposed to having a penis or toy that was just introduced into the empty rectum and removed, to the oral cavity? Is there a good chance that the oral cavity of the people who engage in these acts, are already "cultured" with the same flora and fauna as the anus/rectum and thus have no additional "risk"? I don't know, and would love to.

I personally know couples who have engaged in this for years. They made that choice. They say, to a man and woman, that "they never had any issues". Does that mean anything in a general population? I don't know, but would still love to see real data.

I would love to see some sexologist actually do swab cultures of toys and penis's after they have been in someone's rear end. What grows? What doesn't?

We have done anal kissing and licking, and tongue insertion (you cannot really go very far), for ages. Our friends who do full ATM stuff thought we were nutty for drawing the line there, although I could not, and never did it before.

A few weeks ago, I did it for the first time. Nothing bad happened to me (we were very clean and I would not have touched his penis with my mouth had there been any visible debris or smell. There was neither. I think copious lube, which rubs off coming out of the anal sphincter, may carry most of anything away, in our case (we use gobs of lube).

However, it is not something I would do every day, but would I personally do it again? I have since, and will again. It is an insanely nasty hot turn on for us both. Is there risk? Probably. Is it significant? I simply don't think so in our monogamous relationship (over 30 years) and with us both in good health and with great hygiene before and during sex. I would, however, love to know for sure.

Anyone care to do that study?

Our friends (two couples) who "do it all the time" and have for "years" have strong science backgrounds (I don't want to say more then that, but they understand medical risk). They choose to accept that risk. People do a lot of far more dangerous sexual things (documented risk). Look up the infection rates from piercing or to people who choke themselves for sexual fun.

The big no, no, however, is ass to vagina. That is a complete no go, since the vagina is a completely different environment and will get infected, and unlike the mouth, has no digestive enzymes, is not part of the digestive tract (as the ass and mouth both are) and has no stomach full of acid to kill things off (as the mouth has, just "below it". Also, the sterile urethra is right there and you do not want fecal material anywhere near it, which will indeed giving one a raging UTI infection. Thus, Ass to Vagina (despite some porn videos showing it) should be a serious red line, no, no.

I hope that makes sense, although it doesn't really answer your question...which is a great question and one for which there were some clear, scientifically documented data. If you find some...if anyone does, please, please post the links. We could all learn something.

Thanks