Ahem, "technically", in dressage, there are three different seat positions. The "neutral seat", where your weight is balanced straight down on your two seat bones and your lower back is pretty straight/flat/vertical, the "forward" seat (used briefly when stopping), where you allow your lower back to arch inward very slightly and thus your weight, although still mostly on the two seat bones of course, also tips slightly forward onto the pubic bone as well. Then there is the third position, often called the "pushing" position, which is the opposite of the "forward" position. Your lower back rounds slightly and you sort of "tuck your tail under" thus distributing your weight on mostly on the two seat bones, but also somewhat on your tail bone area. That position is used to urge the horse to collect or move forward.
The "neutral" position is the one that is used in dressage most of the time. The other two are only used briefly "as needed" to get a specific response from the horse. This, by the way, is exactly as it is in WESTERN riding.
Oh, and none of the above has anything to do with the position of the rider's leg (except by default). A dressage rider's legs should be very long, similar to a western rider's leg, although some western riders use a "chair seat" which is not correct for dressage. A dressage seat, when viewed from the side, should appear closer to a "standing" position than a "sitting" position. If you stand on the ground naturally, with your feet spread apart a bit, then bend your knees slightly, you have the correct dressage position (side view). When you are on the horse in this position, your legs are to hang long and "drape" naturally down the sides of the horse without gripping (very similar to Western).
This is partly way I say that dressage is more like western than it is like hunt/English seat.
There are apparently different meanings to the term "two point". In my jumping days I was always taught that "two point" meant only contact with your legs. NO contact with your seat at all. So you are standing in the stirrups and resting your TWO KNEES against the horse, with your body in a forward position.
Last edited by Myya; 07-13-2013 at 12:36 AM.