The correct seat is the basic of all good riding “with the horse” and not against it. In the calssical sense of riding it’s a whole system which has to work, if you want to get harmony between horse and rider. Only if you have the cooperation of the back of your horse (only than) you can start to flex the hanches. For getting this status it needs tons of correct riding without tipps and tricks and work for both parties. But this work is never ever against the horse, because it’s our work to make us understandable for our horse and it is NOT the job of the horse to understand inconsequent and therefore inconsistence aids of the rider!