Join Date: Dec 2010
Location: southern Arizona
It could be that cantering is more fun than she can responsibly handle right now. It could be you need to canter enough that it stops being so intoxicating. It could be your balance is too forward, which some interpret as 'go fast'. It could be your lower leg bounces at a canter, and encourages speed. Can you provide more details - does it happen with all horses you ride, just this one, etc? And pictures might help...
"Make the right thing easy and the wrong thing...well, ignore it mostly."