Do what you want when you are alone. If you are with others, then it depends on the type of stim. If it's too weird, it's best to suppress it, or find a non weird alternative stim to use in public. If it's not too weird, there is no need to suppress it.
One of my stims is bouncing a knee rapidly while sitting. This isn't too weird, so it's okay in public. I have occasionally had comments on it, but not often. Rocking or swaying while sitting is sort of in between weird and not weird, so it depends on the situation, but I have occasionally found myself doing it in public. Twirling a utensil or pen/pencil, etc. in your fingers is okay in public. It's kind of like doodling. I have had a few comments about it, but nothing serious. My sister cracked me up by making a comment about my doing it once. At the time she did that, I pointed out to her that she has a habit of shredding tissues and napkins without thinking. People who live in glass houses shouldn't throw stones. Another stim of mine is tapping a foot up and down slowly, but over and over while sitting. This one is okay in public, too, as this doesn't look too weird.
So, do what you want in private, and do a modified--non weird version in public. And remember, stimming involves physical activity, and physical activity burns calories. If someone does bring it up, just tell them you are burning calories.
_________________
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