You are very fast, my horsey ...
Riding is a lot more about balance on the move than gripping with your legs.Try to sit squarely in the saddle, moving your body with your horse. The more tense you are, the more you will bounce. Stay in tune with how he is moving. It will be less likely that you will be to be thrown off balance.Having your weight set further back will help keep you secure if the horse stops suddenly. Think of driving in a car without a seat belt. If the driver suddenly hits the brakes you’ll go flying forward.Same thing on a horse except you won’t have the seat belt to keep you in the saddle! The same is true if you are sitting too far back on the horse, if he heads off quickly you’ll be left behind.