I have uke hold my wrists and push them towards my body, trapping them at the top of leg groin area ( a groundpath is established of course). Then I imagine this - My arms are like two ropes and have no strength of their own. My one point/hara/dantien call it what you will is like a balloon that has pressure inside it. The pressure from the uke on the outside is eqaul to the pressure from the hara on the inside, there is equilibrium and my hands are 'trapped' between the two opposing forces. Then and this is where the interesting stuff starts, I mentally increase the pressure/ki from the inside, so the balloon starts to get bigger and bigger. At all times I feel my hands and arms are like innocent bystanders, as they remain squashed between uke and the internal pressure of the balloon. As a connection has already been made with uke at the start, I never fail to move uke backwards with surprising ease.
I finally got to try this exercise and it's eerie how easily it works.
I tried it with a friend who is not my student and who has often surprised me with what he can do. In agete, for instance, he can often raise his hands very effortlessly before I can resist, but when I try it, he feels me moving and can lock down and seal me off.
This time, though, I did as you described and he just floated back. Time after time, he couldn't resist. Very interesting.
Then I did agete the way Dan showed me. I could never get it before: it involves letting his power go down the front of your body, into your feet, down into the ground and back up under the opponent's feet, going up into his body. At the same time, your own power goes up your back, out the top of your head and over the opponent to come down behind him. And then you just raise your hands straight up and he can't resist.
In the past, I have been unable to sustain both of these directions of intent at the same time and I've never been able to make this agete work on this particular training partner.
This time, I used my ki to direct where the force would go. If you tell me, put your mind here and also there, I couldn't do it. I could establish the power down my front and up into him, but when I tried to bring my my own power up my back, I lost the power in front. Because I was trying to put my mind in both places at once.
This time, using ki, it was like saying put one hand here and the other hand over there. The mind doesn't do it: it directs the ki to do it. I can reach into both places at once with my ki and sustain it in both places at once because, again, the ki is a part of me like my hand(s). I can put my hands in two places at once, but my mind is pretty singular. I've only been able to put it in one place at a time. But my ki is just like my hands: I can put it where I want it and keep it there while also doing something else. The mind just directs and observes.
So I was able to set up both types of intent and then I just lifted my hands straight up and my friend was unable to stop me. He could feel it and could tighten down on it, but when he did that, his feet would come off the ground and he would "float" back several inches. And I felt like I wasn't making any effort at all. It was really a blast and very satisfying.
Except for one thing: he could let go (or my hands just broke through his grip). I remember when Rob John did agete with me, his arms were spaghetti but I couldn't feel him moving, I couldn't stop him and I couldn't let go. If he had brought his hands back down, I still wouldn't have been able to let go and he would have given me whiplash.
So I've made some sudden and very interesting progress but I'm clearly still missing something subtle.
So I still have something to find.
Best to you and thanks for the tip.