Thanks Mike. Aha, is it this one? Damn and blast, I have the brand new version of the book which revised this exercise out of it.
http://www.aikiweb.com/forums/showthread.php?t=12124
I'm also going to try the exercise you suggested in post 2 of this really excellent thread. I'm finding I can feel the pressure more strongly with this exercise than the Ki society exercises.
http://www.aikiweb.com/forums/showthread.php?t=10809