I've always wanted to try something anal with my gf, like at least finger her or something but she told me that she's never done anything like that and soiunded like she never would think about it, how could possibli do it with her?
Try rimming her, but make sure you're both clean and fresh, then tell her you want to orally please her doggie style and start at her anus. Either she will really enjoy it, or stop you right away.
You could slip subtle hints in for a while. Very few people will take something as socially taboo as the suggestion to try anal and pounce on it right away. Work her up to it. Ghost's idea was a good one.
Personally- I love a vibrator there. Or could use one of the vibs with the attatched "clit" bunny/beaver/whatever and put it in her then turn the critter around to touch her back door while you lick her clit. Fun way to come, I think.
Never ever push her into something she doesn't want to do though. She'll dispise you for it later more likely then not.
Try watching an adult film with some tasteful anal scenes. There's one called "After Midnight," with Gina Ryder, that has a really hot scene at the end where she gets anal for the first time. Then discuss it afterward.
I got my wife into anal using the advice from Vixandra; working slowly into it. During oral sex, I'd VERY lightly stroke the area just around her anus, then over a period of weeks, would work my finger further and further, until her ass almost pulled my finger in on its own. Finally, after a couple of years, she actually asked for me to put my cock in there and now loves all kinds of anal play.
Good luck and take your time. And if she still won't, accept it and love her regardless.
When it comes to trying new things, and wanting a partner to go along with it, there is only one rule that applies: Respect and patience.
If she doesn't want to, there is not much you can do really. Unless she gives hints and makes it clear she is open for the idea - just not at the present time.
What you can do, as mentioned by others here, is to slowly giving her a taste of it, by watching movies together, or use magazines. Find stories or articles where women talk about their experience with anal sex. Maybe she will look differently on trying it then?
Just respect her limits at all times, and don't push it - then she will probably resist it even more...
My advice is be prepared to endure it yourself...when my ex asked to do that sort of thing I said only if he'd let me do it to him first. It was a trust thing....but yeah he didn't like it, and me....eh :: shrug:: I could go either way really.
My guy got me to do it my using my own lubrication to just rub the little pucker in circles during oral. Stimulate the skin there, so to speak. Stimulation is GOOOOOOOD. Then we moved easily onto fingers and eventually penetration.