Thanks Budd, and thanks Marc for the original excercise.
Here are some thoughts I have, take them as you will.
What about, when one exhales, the area from the diaphragm downwards doesn't "rise", rather the pressure sensation created in the lower body by the inhalation/breath is conciously maintained? This pressure allows the spine to "rise/stretch" naturally.
The reason I asked about the spine was because the upper body, as I see it, should also include connection of skull and spine. If the skull is correctly balanced, the breath should do a lot of the stretching naturally.
Does this correspond with what you mean by "packing"?
I would say so - since the lower body is generating the impulse and the "store" happens up through the torso (as part of the connected unit, that's crucial). Skull/head hanging by a string through the top of the head, alignment good - check - will help propagate everything. How well and purely you can manage the stored pressure will result in the "stuff" that happens when someone touches you.