Seriously, it is well known that a lot of women just CAN’T achieve an orgasm. I do not think it is necessarily all in their mind. I for one can have an orgasm each and every time with oral sex, but not all the time during penetration. It is not that I am not in the mood or don’t enjoy what is going on. I just don’t seems to be as physically aroused, though I may be mentally. And size doesn’t matter either. They have done studies on why women can’t orgasm as well as men etc. and then they started focusing on viagra for women to help them with orgasms. Then there are times that I am still aroused from the oral (since we have oral sex close to every time before we have sex) and I can cum during vaginal sex without a problem. I have no idea why this is and I don’t fret over it either, nor does my husband (anymore) as long as he can make me cum during oral sex he is happy. He feels he has completed the better part of the task.
Of course, there are women who have no problem having orgasms (or so I am told), but then there are a lot of “fakers” out there as well.