Women can orgasm through anal stimulation, but through anal stimulation alone it's unlikely. Just like it's more difficult to achieve vaginal orgasm versus clitoral.
I've never received anal before, so I can't speak from experience. Typically women either love it or hate it, and then there's the in between of the women who are too scared to try in fear of pain or various other moral reasons.
on askmen.com you get this:
Why does she love anal sex?
Because anal sex feels good
Women love anal sex because it can feel absolutely incredible. It's different in sensation and it doesn’t feel like anything else she may have felt before -- it's deep inside, it's not her clitoris and is not in her vagina, but feels strangely like both in a sort of mixed-up combination in another part of her body. The rectum, once it’s ready, literally swallows the penis up and can’t get enough. The back passage transforms itself into a sexual playground. If the clitoris and/or vagina are stimulated while you are inside of her, it can take her to another sexual realm. Anal orgasms are possible.
Because anal sex is naughty
People love to be a little bit naughty sometimes, and anal sex is one of those things you can do completely privately, and nobody will ever know you were naughty except you and your partner -- which is part of the fun. It is also often a "first time for everything" type of activity which can also be nice -- doing something you've never done before, ever.
why does she hate anal sex?
Because anal sex hurts
Anal sex is not easy to master when you haven’t done it before. For a man it may seem straight forward -- in, out -- but it isn’t this simple. Women hate anal sex primarily because it hurts. It can cause cold sweats, shivers, extreme agony, and a massive chemical release into the blood stream that causes pain. This is highly unpleasant, but may be endured because A) She wants to like it; and B) She wants you to like it.
If you're not very careful, if you don’t warm her up properly, if you don’t go slowly enough, you will probably hurt her. This really minimizes your chances for trying anal sex again. Do your best every time and you have at least a fighting chance at having another go.
Because she's worried about a mess
Anal sex is obviously a hot spot for mess. The idea that you could penetrate her butt and come out in a sticky situation is hugely embarrassing for her before it’s even happened, and for this reason she may avoid anal sex altogether. Women spend so much time making themselves look and smell beautiful that to have something ruin her hard work can be mildly devastating. Worrying about mess can be alleviated by using an anal douche before engaging in any anal play. Try taking a shower together too, and make sure her bowels are emptied at least an hour before starting.
What not to do
Do not ever put your penis into a woman’s body without her express permission. Do not treat her body like a scoring device. She is not an object for you to ejaculate in or on, and if she is kind enough to share her beautiful butt with you, treat it with respect and be happy you were allowed close enough to breathe her in at all. Don’t ejaculate inside of her if requested not to. Don’t slam, jackhammer or be forceful either.
what to always do
Always use lube.
Always wear a condom if requested to without acting like a baby. Do as you are asked at all times -- anal sex is a delicate situation and she needs to be able to trust you.
Gender presumptions and anal sex
When a heterosexual couple thinks of anal sex, it is generally man-in-woman anal sex. To get a good understanding of what it's like -- and how to improve your performance -- it is necessary and helpful for you to open your mind to the possibility that anal sex is not something that only you do to your female lover, but something that you could do to each other.
Scared yet? Don’t be. If it’s good for the goose, it’s good for the gander. Anal sex takes a lot of practice to perfect, and experimenting with one another is a fantastic way to deepen your connection and enhance your sex life and relationship. It does not have to involve sex toys. You can use fingers, tongues, oils, lubes, and any number of other things. Experiment, and let your own body be loved. It will pay off.
Backdoor shenanigans
Anal sex is many things to many people. Do it right, and you’ll get to do it again. Do it wrong, and you may be doomed forever. Well, probably not forever but until she forgets how bad it was the first time around.
There are hundreds of anal sex guides online -- explicit instructions on how to do it right. If you read at least a dozen of them, you’ll probably have a good idea about how to start off. The best piece of advice we can give you is to make sure she is hot for it before you start. Then you really can’t lose.
There. A long winded post of primarily copy/paste from a simple Google search. Take what you want from it ;p