If you're faking satisfaction in the sack, you may not be fooling anyone.

A study (out of Canada) found that men and women in a relationship "have fairly accurate and unbiased perceptions of their partners' sexual satisfaction."

That means people are pretty accurate in gauging their partner's satisfaction levels,especially women. Men in the study "slightly underestimated their partners' levels of sexual satisfaction."

Two factors affect a person’s accuracy: their quality of communication and relationship satisfaction.