I’ve been looking for an opportunity to brag about the forty-five minute climax I gave my wife a few weeks ago, and this is as good a place as any.
This seems to me to be an excellent observation on your part. Tension is definitely not conducive to enjoyable sex. It’s playtime, and playtime is fun. Otherwise it’s work, and you don’t want sex to be work. I think the other posters have a good point, that the two of you might be looking to the orgasm as an ultimate objective, and this sense of a “goal” might be causing her to freeze up. There’s a lot more to it than that, naturally. Why, just the other night, I had my own climax, and then continued the play and brought my wife to two separate orgasms in the fifteen minutes following. </smug>
It’s possible that your girlfriend’s tension is caused by some traumatic indicent in her past; I dated a woman for a while who had been abused as a kid, and we took the sex nice and slow and safe. Dunno if that’s what’s going on here, but it’s possible.
Here’s what I’d recommend: Get intimate without sex or without any possibility of an orgasm being an ultimate goal. Get some oil and give her a long, slow, head-to-toe massage. It should take at least an hour. Don’t focus on playing with or rubbing any of her “magic places,” because you don’t want this to seem like foreplay. It’s entirely to let you enjoy her body, and to let her enjoy you enjoying her body. She’ll have a nice, warm glow afterward, and if her sexual tension is being caused by anxiety about not being able to reach a “goal,” this intimate and sensual experience may help her to associate your physical contact with pleasurable feelings without worrying about the sex part.
Do this a couple of times, all without initiating sexual contact. (If you’re worried about getting off yourself, try masturbating in front of her. Aside from providing for your own needs, it may also help for her to see you pleasuring yourself.) The third or fourth time, do the massage for fifteen or twenty minutes, starting with the feet and traveling up the thighs. When you get to the top of the thighs, give her a nice, slow, casual rub in the magic triangle. Don’t do the fast clitoral rub or anything, because again, this is not about “going after” the orgasm. Spend a few minutes massaging her labia, etc. Then move on. Continue the massage around the rest of her body. You can come back to the groin area, but like I said, this is about pure sensuality and pleasure, not about “trying to get an orgasm.”
All the while, listen to her. She’ll make noises when you do stuff she likes: feet, shoulders, neck, whatever; every woman is different. Don’t zero in on those areas exclusively, because too much of a good thing can ruin it, but do give them an extra bit of attention in and around everything else.
The point of this is in physical comfort and relaxation, as opposed to an athlete trying to jump over the bar. It can work wonders; by the fourth or fifth massage, she may be relaxed enough to “naturally” relax into an orgasm. If you’re both paying attention, you’ll know when this time comes.
Good luck, and happy shagging.