Crossing your legs in a skirt or dress, just sounds sensible to me. I've crossed my legs so often, in both guy and girl mode, that it comes natural to me. That being said, I have also discovered that crossing them too long can weaken your legs, cut off circulation, sometimes, unnoticeably until you stand up and walk. After several times of my leg falling asleep, and then tripping over myself in the grocery store, I am a lot more self conscious about leg crossing. Cross your legs at the ankle, if you want to cross them, but more importantly, keep your knees together. I think the idea of just taking up less space than a man is key. Elbows in, knees together, whether sitting or standing.