Tehee- I must be lucky. Before I met the guy I am with now, I didn't know what an orgasm was supposed to feel like. But boy oh boy, do I look forward to them now!!! He can get me to orgasm through any kind of stimulation- sex, his tongue, fingers.. and might I add more than one at a time!!! Yes, I am a very lucky girl!

If there are expectations and she is worried that she wont orgasm, she wont. Make it heat of the moment and take your time! Don't rush through so you orgasm- some girls just take time. Talk dirty, breathe hard, go down on her for a while- anything to turn her on. Most importantly, be gentle. I was with one guy who was too rough and it was not at all enjoyable. If she is squirming away from you, it clearly hurts! Hmm, what else.. you can tell her to randomly think of things that she finds are a turn-on (things that she finds hot)- just don't tell her this during. Don't talk about her orgasming while you're in the bedroom. Discuss it when you're just hanging out- and don't make sex planned. Just pounce. Pull hair, hold "lovehandles" and allow her to just let loose (make it no-holds barred). Maybe she just needs a little encouragement, but it will come. Also, ask her what she likes- good communication is KEY!
I'll ask my guy if he's got any tips for ya, good luck!!!!

My GF and I had a similar problem the first couple of weeks. The problem was completely mental. As soon as she became comfotable with me we talked about it as I went through the motions to see what she thought and how she felt. One day I took and long time teasing her by running my fingers very lightly and slowly all over her body. Perhaps you need to take sometime destroying a mental block together by exploring together.