Just a little more on yin ru, yang chu; yang ru yin chu...the principle can be applied to the point of contact (yin being the external flesh yang being the bone marrow) it is also a small circle from the point of contact to the dantian and opposite 'yao' (waist) and thirdly a large circle from opposite foot to the small circle at the dan tian and then over the opponent (It should be yin going down the chest and yang going up the back). Another principle at work here is "tun, tu" (or swallow and spit out), when he does it with one hand the swallow is very small and the yin ru yang chu principle is 3 tight small circles. Later he shows it more obviously with 2 hands.
This is very interesting (thank you very much), and I've been thinking about this for a while. Any chance you can point to a drawing or schematic? I want to make sure i'm tracking your meaning...i think i am...but ...