When I first started to research Lucid dreaming, I also researched sleep paralysis and "old hag" experience. I remember reading that sleep paralysis accompanied by a malevolent attacker only or mostly happens to people who sleep on their backs. This makes some sense because most people feel pressure on their chest, which would mean the "old hag" would be sitting on their chest.
I always sleep on my stomach, and the only time I experienced SP was when I experimented sleeping on my back to see what would happen. Has anyone ever had sleep paralysis or "old hag" when NOT sleeping on their back?