Why wouldn't you want that??

Hey people...
There is another subject me and friends discuss alot, but we can't figure it out yet :(
I hope some of you women can help us shed some light on the subject.

Okay..

A while ago i was talking to girl i know.
We were talking about sex ( don't we always lol ).
She told me that she doesn't want to receive any, she only wants to give...
Can you believe how shocked i was????
So i asked her why don't you wanna receive any?!
The only thing she said was : " just because "
She got a little agitated, so i left it at that.

I don't need to get into why i can not believe it lol, but i do want to know why some women choose not to receive ( this girl i know isn't the only one ).

Can somebody out there explain this to me? '