The turn on the forehand is a useful maneuver in teaching the horse to move away from your leg. It is usually taught to a horse early in his training since it requires no collection or shift of weight to his hindquarters. As the title describes, it is a turn around the front end of the horse where the majority of weight remains on the front legs.
Begin with the horse walking a few feet away from the arena fence or wall. Turn his head toward the wall with the rein and at the same time apply your outside leg (the leg closest to the wall) against his side. Keep your seat in the center of the saddle with your weight forward and your outside hip (hip closest to the wall) just slightly ahead. The horse should stop and begin to turn his hindquarters around his front.
Ask for one step at a time. Gauge how many steps you will ask for based on his understanding of what you ask. If he moves away from you leg willingly, ask for more until you have made a 180-degree turn. If he is only capable of giving you one step where his front end is still and his back end begins to move around, accept that one step and move forward freely at the walk. After a few walking steps try again.
If he does not willingly move away increase the leg pressure by tapping your outside heel on his side and applying your other leg to encourage him to move forward. Meanwhile keep tension on the rein closest to the fence. If he continues to resist you may get an assistant who will push at his side with her thumb where you are applying your leg. When the horse no longer resists your leg, you no longer need the assistant. If you do not have an assistant, dismount and teach the horse to move away from your thumb. Then remount and apply your leg. You should notice an improvement.
As he improves his willingness to move away from your leg, reduce the amount of rein until you are merely tipping his head in the direction he will go. When he turns 180 degrees with no resistance, move away from the fence and ask for the same movement. This time you will need to use a holding outside rein as you ask for the bend with your inside rein. This holding rein is to keep the horse from moving off.
Make sure to teach the horse to go in both directions. When you teach one direction, you will need to start from the beginning in the other direction. Be patient, he will likely be better in one direction than the other, just like you are right handed or left handed.