No if's, and's or butts

I can't offer statistics but I can offer reasoning, although maybe you could find a good anatomy/physiology site which depicts both the internal sideview of the male pelvis and the nerve distribution to help. Basically, the prostate is easily accesible through the anus and that's one way anal stimulation feels good for guys. Any guy whose prostate is stimulated will feel pleasure as long as the method doesn't cause them too much displeasure. Consider that when veterinarians collect semen from bulls and other animals for artificial insemination they often use stimulation of the prostate in one way or another.
Secondly, there are just a lot of nerve endings around the buttocks and anus so stimulation there feels good even if you don't go as far as prostate stimulation.

There you have it. Even though the CHAKSTER doesn't enjoy it, a finger in the ass is perfectly natural. So no, you wont get in trouble.
xoxoxo
-c

*sigh* i'm in love

With Chaki or with Mr Cross-Section?

I can confirm that is how they do it with Tigers. I should know, I am one...