Okay so I understand the basic logic of this. But I have a real difficulty in that I can't seem to fix "inside" and "outside" in my mind. If you're riding normally around the arena (so not going across a diagonal etc), which is the inside and which is the outside?
Am I right in thinking that your inside leg is the one towards the middle of the arena and your outside hand towards the arena rails, so you're effectively pushing the horse in towards the rails and framing/holding with the hand nearest the rails? But then how does that work with the idea that the rein towards the middle of the arena should always be open?
I've tried googling diagrams but not having much use and no matter how many times my instructor tells me which is which I can't seem to stick it in my mind.