Try tying his legs together. At the stables this morning, two Shetlands were turned out together for the second time. They were tearing around but there was no kicking (some bucking though) and little nipping. After about 10 minutes they settled down to eat hay. They were having such fun - tails in the air and prancing. Watching a Shetland prance is quite funny!
One of the other owners who was watching suggested, in all seriousness, that we should hobble them to stop them running around.