If you want to learn how to lunge a horse, don’t use a round yard; your horse will simply run round and round the fence without learning anything.
To lunge a horse, start in a twenty foot square yard with a plain headstall and lead rope on your horse. Teach him to walk a circle around you when you stand in the centre of the yard. After two or three circles to the left, ask you horse to walk right up to you in the centre of the yard. Rub his head for a minute or two and let him relax, then ask him to walk a circle around you to the right.
Spend at least one week of twenty minute lessons, teaching your horse to walk and trot around you in this manner. Don’t move out of the small square yard until the lessons are well established.
Gradually make the circles larger and always ask your horse to walk to you in the centre of the circle for a rub and a break. Then you can ask him to walk or trot around in the other direction. Your horse must not stop, start or change direction unless you ask him to.
Never lunge a horse in side-reins or restraints.