As for you, if you are paying for them and worry about such shit, I suggest you have visit to SAAFE. That should bring you back to reality.
I have visited SAAFE, and it's clear that the picture is mixed. Some of the girls on their never cum and often fake it, some sometimes do, some do a lot.
It's important to me that the girl enjoys it as much as possible. That gives me pleassure, and since I'm paying for pleasure, a girl having an orgasm or two makes it a much better punt. In terms of "how do you know if it's real":
- probably not a good idea to see high volume girls. Search out the part-timers with another job, or who only see 1 or 2 people a day
- use your nose. I don't think there's been a lube invented yet that smells of female arousal/ cum.
- ask the girl what turns her on. One regular has very particular requirements, and so we go with that. Some girls will tell you what they want. Ask them?
- tell the girl you like to see her cum and, if your efforts fail, she'll probably be more than willing to play with herself/ use a doxy to completion
-if a girl squirts, and preferably all over you, that's a pretty genuine sign of arousal.