I don't know what the experts say about it, but I had the hop too when I started out. Basically what I did to stop it was to start the re-mount swing earlier. The reason you are hopping is that you are bringing your leg up and over at a time when you have no energy left from your push off with the left foot so the little hop is your body's way of generating little more umph. Think about this. When you are running your left foot hits the ground in front, then you bend your knee in preparation for the push off that drives you forward. Normally your right foot would be coming forward at the same time your left leg is 'coming back' after the push off. Well, instead of bringing the right leg forward for a running step you are re-mounting. That push off time is the moment when you start your remount. You use the energy from the spring action of your left leg's push off to bring your right leg up and forward for the remount. It's like you are doing a really funny walk step with your right leg. You are using some of the energy from your left leg's step to get you up and over the saddle. You can do it at any speed too. And the further you get your left leg forward the more time you have to do the re-mount. So if you take a big step and a do a big push off you can do a really slow re-mount, but it still works exactly the same.