Okay, I can't believe I'm admitting this! :blushing: But I have been known to fidget when I'm learning too! Drives my husband batty. Now, not like my 5 yo... who btw sounds exactly like yours. I laugh at him when dh is teaching him because he will try to sit so still but something has to move or he will just plain fall off the chair! For me, I will do some kind of motion with my fingers or I don't know some kind of movement. But! Interestingly enough, I catch onto something faster that way. My dh thinks I'm not listening but I'm totally present and have all concentration on what he's saying. Can even usually give his words back to him verbatim. And yes, I have a somewhat busy, you could say, personality too! I'm not hyper, can sit still but I just move always in high gear. Even my thinking!
Anyway for my ds, if I'm trying to get some measure of stillness from him I usually hand him a toy to hold and work with in his hands. Keeps the rest of him still to be moving his hands. Or a crayon and paper to do squiggles on.