Moon-Earth Sketches

For our purposes there is actually nothing so special about the Moon and the Earth. They are only names and for convenience, the situation holds just the same for any two orbiting bodies:

Moon-Earth; moon-planet; planet-Sun; binary stars or a pair of black holes etc.

The model should work better with large masses, close proximity and fast rotation but not to extremes because you will have relativistic influence, and the bodies should be comparable there must be a bit of balance.