I am a 27yr old female, been married and divorced, been through a few men and women.
Quite frankly, I think you all need to re-think this.
My favorite part about masterbating is doing it WITH my partner. He loves watching me and I love being watched. I also love seeing him let go.
Also - since there are two threads here - the more a woman, or for that matter a man, knows himself, the better sex will be. You'll both be able to show and tell each other what you actually like and want.
Don't feel ashamed about knowing what you want. Don't feel ashamed about how you think you look. Just do it. Just let go. It's the most perfect gift you can give your partner - trust - you trust them enough to let go in front of them. It doesn't always mean they weren't satisfied with sex - it's just a differnt kind of orgasm.
And, may I say, women, like men, are built in many different shapes and sizes. My best friend can have an orgasm that includes her clitoris and vagina. I can't - I am simply built further apart. I love masterbating when he's in me, too, and he loves to watch it that much more. It usually makes it more intense for both of us.
Maybe this will help all of you.
Enjoy.