Physical Movement can create neurological signals that affect the brain.
Stimming can be a good thing.
One needs to try to balance the "non-verbal-communication" aspect of it: moving feet under a table or hands out of sight may be more appropriate in some situations where there are other people around. I have several "finger games" I play in situations where "being still" is expected, but I need to move.
In meetings where there is a lot of sitting for a long time I will sometimes get up and move to the back of the room and stretch my legs or do lunges. This is less distracting or socially unacceptable to others than "wiggling in my chair" or bouncing my legs in a sitting position which may shake the floor or table and bother people.
Recently I was driving for hours and I was having trouble concentrating on the road. I couldn't "get up and move". I started lightly tapping my own face in different places with one hand to keep me stimulated and still focused enough to drive.
DBT also advocated movement and physical interaction (such as cold water on your face) as a way to be skilled in dealing with anxiety.
Some of this stuff is psychological but some of it is physical too.
Google DBT Skills.
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ADHD-I(diagnosed) ASD-HF(diagnosed)
RDOS scores - Aspie score 131/200 - neurotypical score 69/200 - very likely Aspie