rewarding bad behavior by allowing him to gait

When my horse gets excited about something he gaits beautifully. I let him do it and praise him for it. But am I really praising him for the gait or the behavior? Of course I want him to gait, however, shouldn't he be gaiting when asked and not just because he's excited? I don't understand why I have to try so hard to get him to gait when he will just slide right into it when he is excited!
~Maddie

SUSAN: Hi Maddie. It sounds like your horse is being lazy. Yes, he may think you are happy that he's getting excited. You are correct, what we want is to create this movement, or DRIVE by the rider consistently, not just his occasional reaction to his environment.
Maddie, imagine yourself walking along at a relaxed pace, shuffling your feet, with your back slumped as you go. Now, at the same speed, engage your muscles, stand up tall and lift your feet well when you walk in an athletic manner. This is what we want to ask our horse to do.
To create this drive, you want to feel like you are pushing the back end, while essentially holding the front end from speeding up. With his nose in and light contact on the mouth, you will ask him for short bursts of drive. You will use your seat to ask by squeezing your buttocks together and pushing them forward into your hands. At the same time, squeeze your calves lightly to push him forward, yet keep contact on the reins. Do not loosed the reins and do not lean forward in the saddle. At first you will reward just an immediate small reaction of drive, and let him go relaxed again. Then you will ask for bigger and better spurts, as he learns what you want.
I hope this helps, and happy gaited trails!

CAROLINE: Maddie - Unfortunately when horses are at liberty they will do amazing things, and one of the great things about training them is that they can be taught to do these things under saddle with time. I wonder if taking some lessons or finding a gaited trainer inn your area would help the two of you get together on the correct gait and how to do it under control. It is a painstaking chore teaching them how to gait slowly but the payoffs are worth it. There is nothing like a great walking horse to carry you down the trail. Are you sure he is gaiting in a flat walk when excited and not trotting or racking? I would not praise him for getting excited under saddle for fear it will build into rearing or crow hopping later on. It should always be the riders idea to increase speed, not following the horse's cues. Not having seen your horse move or his behavior, my advice would be to do some round pen work: controlling his speed at liberty. Then you can practice in the saddle speeding his gait up when it is at your command, not his excited reaction.