Where's the confusion? *possible spoiler*
The fact that there are so many threads stating "OMG, I can't believe they showed vaginas!!!" goes to show that many of the posters on this board completely missed the point of this film.
It isn't porn. It isn't even a plot per se. It is a visual deconstruction of the female anatomy and sexual process. Playing with uncomfortable subjects such as female-orgasm/masturbation/menustration/full frontal nudity/and of course, the vagina. All of which are aspects of normal, healthy life.
If this film made you squeamish. Good. That was the intent. It is a film that aims to expose the misconceptions men have about the female body and the power struggle that is heterosexuality.
"It's muffin time...
Muffa-muffa-muffin time!"