The horse is twitched. This practice is primarily used as a means of restraint. You can see that his upper lip has pulled through a loop, then the loop tightened by twisting the handle attached to the loop. The bottom lip is also twitched, and in this case it looks as if it's attached to some sort of rein mechanism, so if the rein is pulled, the lip will be pulled away from the gum and could cause pain and damage to the lip and gum. I don't know what is in the horse's mouth, some kind of metal contraption perhaps. The position of the head is a normal position for a horse that is "twitched". It's sad that this is considered a celebration.