Lol one time my coach made me pretend that I had two baby chicks in my hands, and if I squeezed too hard their heads would pop off. Kind of gruesome but it got the point across.
Hold two water balloons or eggs in your hands. Maybe even tennis balls or golf balls - anything that will make it hard for your hands to be holding the reins tightly/toughly.
Have a friend hold on to the middle of a rope with both hands.
Stand behind friend, hold both ends of the rope in your hands (reins).
Then drive your friend.
Now - switch and let your friend drive you.
You'll be amazed at how subtle your hands need to be to communicate. Especially when you realize it's on a piece of metal held in someone's mouth.
I agree with T. a. Eyo! Try to ride more with your legs and you can start your lesson by keeping your reins very long.
It comes from not using enough of your leg and seat to correct and guide your horse. Try going around the ring and adjusting your horse's stride with just your seat/leg on a light contact. You can also try riding on a lungeline with no reins.
Hi Kareen. This is not an easy fault to correct. Try to focus on your hands, all the time. Try to release the pressure on the horse's mouth. With practice and patience I'm sure you can do it!