Ack body sway! That cursed cursed movement! As you can tell, I had problems with it as well.
I assume that you mean the Fox Trot body sway that you get from your chasses right? Well, the way that it was described to me was that imagine that as you as moving to your side, you're trying to place your rib cage up on a shelf. You're not leading with the hips or the shoulder, your shoulder moves up slightly to compensate but you're leading with the rib cage.
What I suggest is that you stand in front of a mirror and practicing segragating your body. Keep your feet planted and start practicing leading to each side with your hips...... and then your ribs... and then your shoulders and back down until you can feel each section moving as it's own seperate entity. Hopefully you'll feel them seperately and will be able to add that into your dancing. Take it slow!
~LB
The question everyone should ask themselves before starting each day: Quo Vatamus