Post with one stirrup? 6 weird exercises to help you ride better, but before u post a comment PLEASE READ the whole damn article. Some commenters shouldn't be allowed to drive a car, let alone ride a horse!
EXERCISE 3 With this exercise ensure your horse is absolutely straight on the straight lines in the middle (marked darker in the picture) and that your horse is not leaning on the inner shoulder. Ride this on both leads in walk and trot.