Astral projection was a thing that Anthropologist/shamanist/writer Castaneda focused on, and which I experienced briefly.
Two of my psych profs were partners in a Phantom Pain Clinic; where people suffered from, say pain in their foot after losing that leg, or in a hand after their arm was amputated.
I was a victim, er subject in a doctoral thesis experiment that taught us how to gain a very relaxed state, and manipulate things like body temperature, heart rate, and such that we were being monitored for... something that could be taught to their patients to help ease the pain.
The technique is now called Autogenic Relaxation and is quite popular today for any kind of stress.
I still practice it, along with breathing exercises like diaphragm breathing.
Controlling the body functions in a very relaxed state was not a matter of command or force, it was a matter of recognizing our feelings when we did see the needle move in the direction we wanted, then recalling those feelings to make it happen as we liked.
Sorta like Michael Jordon in a 'Zone' when shooting 3's; if you can recall how that FEELS, it's easier to do when you want.
So, one suddenly spring afternoon I was doing just that on the third floor of a tower building on campus, hooked up to the monitors, wishing I was outside in the sun... when I, my conscious self in a 'spirit' sort of shape, lifted up out of my body, flew joyously down the stairs and out into the day!
But it, unsurprisingly, freaked me out, and with a bit of a whoosh I flew even faster backwards through the doors, up the stairs and back into my body.
Sorry, no video exists!