All these questions on sway. Why not go to a good teacher preferably one who has proved their worth. Get them to get hold of you in a practise hold and show you. It is a feeling. The guy who reckons that running around a corner is a pivot. We are turning and swaying, not half a turn to come back the way we just left. A bike does it, a bird does it, even cars try to do it. Sounds like a song doesn't it. So lets all sway to assist our turns. But not in Tango.