Hi Diana,
Last November I visited Amanda Richards for a makeover and a photo shoot. During the photo shoot Amanda asked me to cross my legs at the knees and I was unable to comply. She then suggested that if I wanted to cross my left leg over my right knee, I should shift my position so I was sitting on my right hip more. By rotating my position so that I was no longer sitting squarely on my butt, but instead was sitting more towards my right hip, I was able to cross my legs in a very ladylike fashion.
I have also discovered that I am able to accomplish the same exact leg cross in my therapist's office. The coach that I sit on during my sessions has a very soft cushion which I sink into. When sitting on this cushion, my butt sinks lower into the coach and I am also able to cross my legs, in either direction, in a very feminine style.