Well I have been reading stories about anal sex and I have found most of them quite good and very erotic. But in most of the stories I have found that women liked anal sex very much especially old ladies (especially neglected moms) who are either sex starved or have been regularly doing anal sex since young age. Few story writers even wrote that anal virgins liked anal sex a lot and kept asking for more. Personally I have observed that anal sex is not pleasurable if being done for the first time and if the male partner is not doing it correctly.
Another aspect which needs to be ensured is that the receiving partner should also be willing to take a dick up her anus. If the partner is unwilling for anal sex then it is very difficult to do it forcefully as it would certainly damage the anus of the lady and dick of the male partner.
Now here another question arises why men do anal sex with wife or girl friend or insist upon doing it and in my opinion there are following reasons for the act:-
a. Anal sex is a male dominated act and women are in submissive role during the act, hence man enjoys being in a dominating position.
b. Anal sex is a taboo and every one likes to break it.
c. Normally women consider anus to be a forbidden area for sex, touching and playing and men like to cross the line and want to know the hidden secret of women.
d. Anal sex is commonly considered dirty by most women and men try to play dirty.