We often hear about lightness, self-carriage, engagement. This is all about getting your horse more sensitive to light aids. So you can ride with invisible aids, with your horse doing more and you doing less.
How is this possible to do this while your horse does piaffe, tempi changes etc? Use the boiling frog analogy!
When you put a frog in cool water and slowly bring it to a boil, the frog doesn’t notice and boils to death. Whereas if you put a frog straight in boiling water, they jump right out! This is how you have to train your horses.
Use a small aid first, that’s the aid you want the horse to respond to. If they don’t respond, then I do my boiling water. So that I get the frog jumping right of the water. If you do the slow boil, the horse isn’t going to react and they will end up doing less and less while you do more and more.
You want to do less and less, with quieter aids. The rider should be quiet and subtle. It’s not about just getting things done, it’s about the harmony between horse and rider that is developed through this lightness.