You "rise" with the outside shoulder.? Most kids learn the rhyme, "Rise and fall with the leg on the wall."? Meaning if you are trotting in an arena to the right (clockwise), you would post forward when the left shoulder rises.? Of course, you are REALLY posting off the right rear, but most people have trouble at first "feeling" that movement.? It has made a huge improvement in my riding, my balance, and my horses' balance.