wow many different views...
There was a book I read long ago that mentioned, something the Zheng Man-ching with I believe it was Robert Smith's wife....
Where she noted a "wave" that had passed through her before being up rooted as shown in some of the clips...
Teacher Zheng, is said to have said " yes, you'll feel this, if you are relaxed enough. It is the intention that precedes the movement."
For those not, they will simply be uprooted and thrown out...not possible for them to counter something they can't feel...
The constent pressure being referred to is much like.
just enough to keep contact...in this case acting as a conduit..
What is being moved? It's not the physical body but the others center of gravity.. what has to be joined with, is not the others body but their sense of body space...
Change this, and their body will follow...many clips showing this....