I just started exercising a giant Belgian and in doing so, try to get him to canter. Not too many people at the barn are even capable of getting even a little canter out of him. The major problem is that he falls in. Well, not really falls in, but almost does a completely 180. When you ask him to canter, he instantly leans to the side, turns a tight circle, and is almost going the other direction. When I finally get him to canter we do fine on the straightway, but when we turn, he always does the same thing - turning tight and almost in a 180. I use a lot of leg, which helps a little, but I don't know how much more leg I can use. I try to keep him on his hind end as well.
He's a lovely horse and really tries, so I don't really see it as an evasive thing (but it might be... he never stops after he falls in; he'll keep trotting).
Should I ride him and when it comes to the canter lunge him? I've lunged him before and he was able to go around at the canter once (with A LOT of encouragement). Any advice would be helpful. Thanks.