How to Stop a Horse From Rearing up While in the Saddle

Does your horse rear up when trying to get out of doing something you asked her to do? My quarter horse (Juliet) has tried doing this when she doesn't want to listen. Fortune (my Arabian) used to do this as well. There are two ways to stop her from doing this but the one that works with Juliet and worked on Fortune is putting your hand above their poll (in between the ears) so when they toss their head they hit the hand, which makes them go down before they leave the ground. Another way is to have an egg in your hand and have them hit it when they go to rear. I would start with just your hand first and if that doesn't work use the egg.