Stims serve a purpose. They relax, calm, and can even help us focus. As long as it is not harmful, and not too weird in public there is nothing wrong with it. If you have weird public stims, it would be wise to find less weird alternatives, like carrying a squeeze ball around. These are used by people with hand injuries and athletes to strengthen the hands. Another okay public stim is doodling--carry around a pad and something to write/draw with. Bouncing a leg while sitting isn't too weird, lots of people do that--including me. It is often done unconsciously when someone is under stress, but not always while stressed, as it is a stim. I am not always stressed when I do it. If someone ever calls you on it, just tell them that it burns calories. Yet another "safe to use in public" stim is pacing. Lots of people pace--and that also burns calories. Twirling utensils and pens is okay, too. None of those is too weird.
So as long as it doesn't hurt anyone, and isn't too weird when out in public, go ahead and stim--and burn those calories.
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If a man does not keep pace with his companions, perhaps it is because he hears a different drummer.
Let him step to the music which he hears, however measured, or far away.--Henry David Thoreau