Hehehe...sounds like something I can test out while sitting down.
Ok, I realize you're talking about
comparative speeds of the two bodies, in relation to each other. On the driver's side, even though they're moving in the same direction, the slower speed of the outer body in relation to the inner body at some point makes it crawl around the inner body (tightening it, so to speak). On the passenger side, that same comparative crawl would have it untighten but/for the threads being reversed.
But aren't we talking about centrifugal force rather than comparative speed being the motivation for the reversed threads? At some point the two bodies are joined together (threaded on) unless some force is acting to pull them apart?
Isn't this the meaning of life?