While 100% in the don't fake it camp, please also remember us men are not mind readers and our equipment works different. Much like with cooking and cleaning, if you don't tell us what we are doing wrong or better yet show us the right way, we are going to assume we did our part cause we got the result we wanted and you didn't complain or ask for something different.
I've noticed a pretty direct correlation with a woman's habit of masturbating and her ability to orgasm during sex. The chick I was seeing just before I went back to college, I'd believe it if you told me that I've played with her clit more than she ever has TO THIS DAY, and guess what? She never once gave me any suggestion on what she wanted me to do, I'm sure because she genuinely didn't know.