hmm...i dont know. all i know is that i always fall asleep on my right side with my right arm under my head, but i hardly ever wake up that way. and when im trying to fall asleep, i roll around alot trying to get comfortable. also, if i get at least 3-4 hours asleep, then ill be fine, i dont need alot, though i like it. =)
i never used to fall out of my bed, but i used to be a major sleepwalker! =D apparently, once i came down stairs and started going up to my parents and saying, "wheres my bunny? I WANT MY BUNNY!" i always laugh when i hear that story, cause i dont remember that at all.