My experience w/ my son and stimming, is him using a jargon no one else can understand at a rapid pace and in a soft voice. It tunes everything else out and he's comfortable and familiar w/ what he's saying. A line from a movie,or a song. It softly drowns out what the person is requesting from him, or a new situation he's put in...it's what he knows vs all this stuff coming at him he's unfamiliar with.
We were at a festival w/ lots of people and towards the end of the street fair it got really crowded. His face was at strangers legs and rear ends(he's 5). So he started doing sign language for all the animals he knows 2 inches from his face. The poor kid, I looked at him and said to my husband, "Put him on your shoulders" then he was ok. Up and out of there he could relax.
So I think some stims you can look for a reason and ease the stress for him, make it easier, and for other stims, maybe it's not so important to do that. Sure he may turn heads, but what part about autism at some point DOESN'T turn heads. Pick your battles.
Hope it helps!;)