Originally Posted by Saskia
Drop your stirrups and move your lower body with horse, don't brace against the movement.
Agreed. You need many sessions of riding at the WALK without stirrups. You need a long leg for many things, including balancing well, and you will wear out your ability to pull your leg forward when you don't have a stirrup to brace against, by riding for an hour or more without the stirrups. I have two 15yo's who ride and help me train. One of them has a chair seat, so she spends the first hour riding my (finished) mare English with the stirrups pulled. She uses a mounting block to get on.
Tip: when you are riding glance down. You should NOT be albe to see your toe. If you can, you have a "chair seat", which describes your current seat. With some work you Can fix that. =D