Button #2 is the shoulder button.  The shoulders are a lateral movement button.  We can use pushing energy on the ground or in the saddle to move the shoulders over.  On the ground, our core with the aid of a whip can send a push to a horse’s shoulder to move away from us laterally.  Blocking energy can keep a pushy shoulder from coming into one’s space.  In the saddle, our leg aids influence the shoulders to move away or block a shoulder from unwanted lateral movement.