Except with tango, there are a lot of figures man leads lady to sway up or sway down , and some fegures no sway only CBM done .
Why ? What is the reason we do or undo?
I thought , it must have its regular pattern.
Andrew Sinkison had showed and talked about it . Unfortunately, I did not understand all what I saw and listened on clip.
ylchen

A few minutes ago, I reviewed the natural turn explaned by Marcus...
soaking music from shoulder through foot, lower, rotate left foot in shoe, on previous 3 count , rotated forward action on your right foot into the position ... I saw the whole left side including left foot level with right foot on & , and continuously swing forward...
Why I noted it after several reviwing ?
Besides definition of CBM, I should be well awre of CBM is generated on previous step, the step having lable and following step or steps affected by CBM.

Too many people , even some coaches or competitors ignored CBM or treated it as isolated action labled on which step. They developed sway on their preparatory step, struggled in too big stride for them, looking wild even stop body movement when they danced natural turn 123, feather step , three step...
I suddently obtain some answer to my previous question , such as why CBM no sway, why and when swing up .How to interprete the CBM which labled on particular step. Further, I digested why my new coach put some steps together as one action . Ithought ,gethering the steps involed by CBM as one unit rather than separated step is better to obtaine continuity of body movement resulting from more reasonable body weight distribution and ball compression under music.
I will use this view to dance with my coach . Let's see what will happen.
ylchen

It seems limited on body swing when I was hold . .
My coatch stared at me and knoked his head several times and said you got remarkable progress , especially in foxtrot ( my fourth lesson with him and second times on foxtrot.), now we can put more higher level of figures into the routine. keeping your head on its position .I said , if you could, please add less hover + devolope together to an 60 years old lady.My belly muscles are lack of strength to hold more than 3 beats of level straight leg ,or let me break them down to save your energy. When 2 hours lesson finish. I drove home in hurry for rest. Eventhough, I am going to stick on it until I can't step .
ylchen

Yichin. Is this an Oversway you are refering to. The stretch is up like a ordinary Sway, with your left leg out wide with the toe pointing and not closing. Then continue stretching more that a normal Sway which will bring your bodies into an arch shaped. The step into the Oversway don't arrive on a bent right knee. Its up and over. The first person to introduce the Oversway probably did it by accident. He got carried away with his second step of the Natural Turn with the sway, and accidently couldn't close the feet together.Thought, that felt good So another step, the Oversway was born.

Sorry, Don, probably, to call that swing up / swing down is better, ( someone called it sway up / sway down.)
which occured when exchaged position , (not oversway). Andrew Sinkinson introduced such technique to matained good connection, center toward center, easy turn ( outside,/ inside ), more attractive outlooking. and effective leading. I thought 3 fallaway , tumble turn, some kinds of weve , outside spin, promenade run in quick step... used such technique.
ylchen

Yichin. Are you refering to the drive on the slow in the Quickstep. Followed by the swing up onto the two quicks. I was once told drive the first step and let it float me onto the two quicks. I was told not to work too hard on the Chasses.The way I was dancing I wouldn't last if I had to dance a full disk 3 1/2 minutes. Let the drive do all the work. The S QQ S. was given to me as, down. up. up. up. lower. It was said I was working the Quicks far to hard. So since then I have worked the slows and let it carry onto the quicks which for me was the way to go. It does create light and shade.