Head to the South Pole
On your belly
Knees bent
elbows under your chest
forehead to the bed
This will raise your stomach off the bed, allowing full breathes of air and keeping your body heat in ( in nature this is cold earth your sleeping on, so heat is vital).
This also makes your body ready in time of attack while your sleeping, your ready to spring into a full run from this position and flee your predator. If a predator finds you sleeping on your back, your LUNCH for the lion, etc.
Sleeping head to the South Pole also keeps you in touch with this big electric motor we call earth.