I have a few points regarding anal sex that I would like to raise, but before I do so, I feel it is appropriate to note that I am male, heterosexual, 25 years old, and a resident of Chicago, four variables which are obviously not shared by all and which undoubtedly affect my views.
I think it is important for everyone to understand that both males and females experience essentially the same physical sensation from anal penetration. There are certain body parts that differ greatly between the sexes, but the asshole is not one of them. Don't be fooled if you find a girl who likes anal sex.... there are plenty of homosexual males who also like anal sex. The bottom line is this: Because assholes are an androgynous body part, taking it up the ass for a girl doesn't feel any different than it would feel for a guy taking it up the ass (notwithstanding the relative size differences between males and females).
Think about it guys. Would you like a big dildo up your ass? I doubt it. Most girls feel the same way. While there are exceptions to every rule, it is without a doubt safe to say that anal sex is painful and that a majority of women do not enjoy the physical sensation it brings.
However, as we all know, sexual pleasure is not strictly physical. There is a very significant psychological element to sexual pleasure. I believe that this is the source from which those who enjoy anal sex derive that enjoyment. There are different ways for a sex act which is physically uncomfortable to otherwise generate psychological pleasure. One such way is for the recipient to derive pleasure from the taboo nature of the act. Another way is to derive pleasure from providing pleasure to one's partner. My point is that even when a girl derives sexual pleasure from anal sex, it is most often psychological, not physical.
Anyways, that's about all I have to say about that.