As a man, after well more than 40 years of using anal sex toys, graduating to very, very large and long toys (use your imagination and then think larger), everything is still in perfect working order. In fact, I am convinced that this “training” has resulted in better voluntary and automatic outer sphincter control. And it certainly results in more “rectal holding capacity” which can be handy on long driving trips.
However, there is one caveat: My personal anal toy use experience and knowing a couple people with anal sex experience, is that there is / may be a period of time in the “training” process when outer sphincter control is weaker. My theory is that a) the body is initially confused by things going in as well as out and b) part of the training needs to include practicing / exercising clenching the outer sphincter for a few seconds (its harder than it sounds) and then relaxing, to build strength there. Whether or not this is a problem for some people, or for how long it is a problem, seems to depend upon the individual, and perhaps ultimately on whether they practice strengthening.
I have had three colonoscopies now, per schedule, all with no problems found.
I asked a doctor who does lots of colonoscopies, about anal sex and anal sex toy use, if he sees problems or concerns in his medical practice. His response was that if one is gentle, uses lots of lube, immediately stops if something hurts, and does not do anything crazy, etc., etc., then in his professional opinion “if it feels good, feel free to do it”.
It is only my individual experience, but for the last 20 years I have had a somewhat enlarged prostate that could possibly be from the anal toy use, but there is no way to know the cause in any one individual case. However, it does seem logical to me as a potential cause.
I do have “just over the normal limit” for PSA (prostate specific antigen, a potential cancer indicator), so a few years ago, my urologist did a prostate sonogram (all was okay), but since the sonogram cannot see everything, just in case, the urologist did a prostate biopsy (VERY NOT FUN getting stuck in the prostate with a large number of large needles) – no problems were found. There can be a correlation between an enlarged prostate (without any cancer) and slightly elevated PSA.
Men: Speaking of PSA, elevated PSA can be caused by “energetic” anal toy use, thus if you “receive” anal toy use, and you are going to have annual lab tests that include PSA testing (which should be done every year or two after a certain age; ask your doctor), I strongly suggest “giving it a rest” for 2-3 weeks prior to the testing. My doctor told me that even just “normal” (i.e. to him he means vaginal) sex within a few days of testing can increase the PSA in test results. (You really don’t want to skew the PSA results by anal toy use and thus have to go through even more tests and expense to make sure that you don’t have prostate cancer.)
Regarding hemorrhoids, I have never had problems with that myself. However, an interesting-to-me anecdotal experience is that one of my female partners who did sometimes have hemorrhoids (from long driving trips or from sitting too long on the toilet reading a book), had NO hemorrhoids when we were active with anal sex. As soon as we stopped (for completely unrelated reasons) having anal sex, the hemorrhoids resumed. I can just imagine the TV ads for the new hemorrhoid “cure” … anal sex!