|What about fore/aft pressure management during a turn or in the air? Even when you are centered over your CM there is a continous change of F/A pressure on the skis.
Very good question. Once you achieve a dynamically balanced position on your skis, the body is stable and you are able "toggle" your skis under you at will (as Max501 describes). This is used not only on carved turns on groomed terrain, but on bumps and ungroomed terrain. It is done by either opening or closing your ankle to promote pressure control either on the ski tips, tails or along the whole length of the ski without loosing contact with the tongue of the boot.
An example is while skiing deep slushy snow that is "sticky". If you pressure the tip of the ski too much, it willstart to stall out as suction builds up. To keep the ski gliding well you can either lean back, which is not a good idea, or you can flex the ankle and press the tail of the ski down, which keeps the shin and tongue contact. When skiing deep snow off piste, I do the same thing if I feel the ski wanting to dive.
On Ice, I open the ankle slightly of the outside ski to keep the tip of the ski engaged through the turn.
All movements should be progressive weather it is for/aft or foot to foot pressure control.