Why cant i fall asleep ..on my back?

So I dont know if i am weird, or if this is normal but...

ive had this odd thing since i was a small kid...
a rather smol bean indeed.
I remember the first time i experienced REM atonia consciously i sharted my pants, reasonably so.
(or would it be termed SP at that point if I'm conscious of it..?)
Over the years i experienced it many times and it scared the living hell out of me, to where id be afraid to fall asleep, until recently, now i can calm myself with just the realization of what it is alone.
Amazing what the light of knowledge can do on ignorance huh? I even had a WILD the other day from the state.
However, there is something odd about it. Every time it happens.

EEEEVERY time i have woken up in this state it has been while on lying on my back.
I'm not sure how i end up on my back......
I cant fall asleep on my back. But some way somehow i end up in the classic sleeping position, at times, and when i do, I'm in for a wild ride- HAH! i made a funny.
Can someone please explain this? because literally, possibly the only thing keeping me from a multitude of lucid dreams it seems, is adjusting my sleeping position.:cackle::cackle:

Why don't you sleep on your side if it is more comfortable?

It is yes, and typically that's how i fall asleep. my preferred method is on my stomach or side. its just, like i said, it seems that any time i fall asleep on my back i can find myself easily in the state where I'm conscious of REM atonia.