You can astral project by relaxing your body and and tricking yourself to stay awake. So your body is asleep and but mind is awake. Then your soul can move around. If you want want to learn more in depth on astral projection I would suggest looking up Ryan cropper on YouTube. Taught me a lot.
I also believe when people do ketamine and "k hole" and say they can literally view their body from above that the same theory applies. Tranquilizes the body but mind stays awake.