When I was a child I stimmed - rolling my head left to right (and even now I still occasionally fall back on that, though it never works).
What does work most often is closing my eyes and focusing on the random patterns that my optic nerve seems to generate in response to a lack of stimulation - I see flashes that resolve to faces, space ships, landscapes, and whatever. I never dwell on these "images" - just let them pass and await the next one. They're usually pretty rapid-fire. At some point I sleep, and wake hours later.
I rarely recall dreaming, though. I sort of feel cheated by that. NT's get to dream all the time, it seems, and they know they did. I just wake up after a period of nothingness, and I'm jealous of folks who say they dreamed of things that I can imagine desiring in my conscious life.