Can you describe what you did? What you did with your hips? What you did with your spine? Did you use any 'tricks' to keep your shoulders from tensing up? Did you use the ball of your foot or your toes in any special fashion?
What I did with my body is entirely secondary to what I did with my mind.
I can tell you that that I didn't consciously do anything with my hips, my spine was upright, and my shoulders completely relaxed. The only 'trick' I use to not tense my shoulders is to not tense them ( sorry Ron I know that that is completely unhelpful )
.I don't know what my feet were doing as all my awareness was out towards uke, I 'guess' one foot was slightly ahead of the other, I will try to be more aware of the foot position next time.
What I did mentally was to feel and accept ukes 'intent' invite in into my centre and then send it back towards him. My mind was ahead of his body so to speak. When he made physical contact with me his mind/ki was already travelling back towards himself, and what he felt was ( his description ) was like a hard rubber post. To be honest that was what my body felt like from the inside.
I have been doing very similar exercises to this for many years, but this particular one my teacher had not shown before.
I belive that all the internal/kokyu skills been discussed here are a pre-requisite to achieving these results.
I hope this description was of some help Ron, but I feel that the internet is pretty poor medium for conveying these skills. I mean, how could I convey the 'correct' timing inherently necessary to perform the exercise?