According to playboy..

That was a wonderful article! Confirms what has always been true for me, too. The relaxation/total absense of anxiety, stress or discomfort (like something as simple as cold feet) makes a huge diff for me. If I'm worried or way stressed or afraid we're going to be overheard or even just too cold, it's a lot harder to hit the high note. We're so different from guys!

This also strengthens a suspicion that I've had for a long time--that women likely have way better sex when they're with someone they know well, love, and are at ease with. Which takes time to build.