You could say that I am an experienced woman when it comes to sex in general but I also have a lot of experience with anal sex. At first it was like it is with everyone, tight, painful etc... but you learn over time. My husband certainly has and now we have great sex. In so many forums and sites I hear of women complaining that it still really hurts so I decided to share my thoughts on it.
For beginners, you should start SLOW, use lots of lubrication, i.e. KY jelly and start with something small, i.e. finger. Slowly work your way to two fingers or more. If the girl is comfortable at that point, he can stimulate her clitoris with either his other finger or better yet, using his tongue. I have found that women like it if you can use all three. One set of fingers slowing pulsating the ass, the other also probing the inside of the love canal (vagina) - (do not mix the fingers! Always think of safety/sanitation). And then he can use his mouth or tongue to either lick or suck the clitoris. The best part is trying to use the fingers that is in her love canal to find her G-spot.
Do these things for awhile, and don't rush it. Guys, the objective for males should be to make her have so many small orgasms first that she wants you to ram your "buddy" into her. If she is comfortable with you to go there, wear a condom, use lots of KY jelly (it's water-based) and insert slowly. Start slow and insert the tip of the penis. Do not go any further until she is comfortable and her ass muscle is relaxed to accept more of your penis.
Then upon her approval, go in further and start pumpming slowly. For the experienced user, you can use the other hand (clean one) to stimulate her clitoris or love canal. Continue and enjoy. Remember to take a shower together once your done.
If you do it right the first time, it will always be a great part of your sex life.
For the experts and committed, you wouldn't need much lubrication or condom. And if she squeezes her ass while you are driving your "buddy", you could cum in seconds. But its worth it from what I'm told.
Note, there are several ways to enjoy anal sex. This is how I do it. I hope I was able to share some experience with some up and cummers out there.