Interesting subject.
My girlfriend used to have amazing orgasms (no squirting, but still). When she was on top and she'd have an orgasm, she'd be shaking and moaning for a good 20 seconds. It was so sexy I can't even ... wow.
Nowadays though she just moans a bit and is able to carry on after like 5 seconds. The thought of her faking even crossed my mind lately. I talked about it with her, and she assured me she wouldn't, as she understands it's better to guide me in getting her to achieve an orgasm then just taking the easy way out and faking, and I believe her. So that gave me some piece of mind, but I just want to see her moaning and shivering uncontrollably again. If that came with a nice squirt that would be such a turn on.
I did read somewhere though that, to her, it should feel like she has to take a leak all of a sudden, which she is supposed to completely let go. Don't know if that's even true or not, but it sounds reasonable. And my girlfriend did tell me a few times she got a sudden urge to use the bathroom really badly (sometimes to the point where she'd stop in the middle of sex because she didn't want to wet my bed). Now I may be getting somewhere, or it may be that she really just has to use the bathroom (which I hope isn't the case

).
Hope I get some more time to read about it soon, because again, this would be such a turn on to me.