My stimming, at least what I think of as being noticeable and obviously autistic stimming, is pretty much exclusively limited to when I'm alone. I do think I do some stuff in public that some folks might consider to be mild stims, but it's definitely not anything too out of the ordinary and not anything I haven't seen some neurotypical people do.
When I was very young, I did all of my stimming in both public and private. But the criticism that I received for doing it in public squashed it there pretty quickly.
That being said, in recent years I have found that I deal with stress a lot more frequently/easily, and since overwhelming stress is a major thing that causes me to stim, there have been more times that I have slipped up a little and did a bit of major stimming in public. But I have to be very overwhelmed for this to happen.