Learning from Babies: Quadruped Stability

The videos tell the story with this one: the same stabilization patterns the baby employs before it embarks on its crawling adventure are the same stabilization patterns you can use with adults to groove rotary stability.

Even the video description provided by the parent is prescient ("She's up on her hands and knees, she's got the strength, and she's figured out forward motion. Now she just needs to trust her hands.")

Notice the common progression when using the quadruped rocking drill...begin with all four limbs in contact with the floor.  As stabilization improves, remove a point of contact and test whether stability remains.  The ball is a tactile aid to encourage proper stabilization.