Hot, sweaty sex? Yes, please. Breaking out in a sweat means her body is at a high level of tension and her muscles are working overtime -- her breathing, heart rate and blood pressure are all up. So, once you both collapse into a sweaty heap afterward, you'll know she's been pleased.
Other important signs
- She may arch her back and feet, have uncontrolled twitches in her limbs (during and after orgasm), and have uncontrolled facial expressions (aka her "orgasm face").
- Check her cheeks and neck to see if they are flushed.
- Of particular importance is what she does immediately after sex: Does she leap right out of bed and get on with her day? Or does she go to the washroom and lock the door? The chemical effect of an orgasm on the body brings a dazed look to the eyes and she may just want to laze for a few minutes to enjoy it. If she is missing this post-coital bliss, be suspicious.
- Her nipples will also harden; it has been estimated that there is a 95% chance that if her nipples aren't hard, she didn't orgasm.
- Her clitoris gets very sensitive right after orgasm, so if she doesn't slow down or stop completely after her orgasm, she is probably a faker.
- Making coherent sentences far too loudly is also a clue to her (dis)honesty; she shouldn't really be able to say anything much other than "Oh my God!" if the job is getting done to standard. Anything remotely porn-like is highly suspicious (loud over-exaggerated moaning, etc.) because porn sex is not real sex.