When you position yourself to sleep, where are your arms? Are they inside the covers or outside the covers? If you sleep on your back are they on your sides? If you sleep on your side where do you put them?
I sleep on my side, usually the left, and I wrap my arms around around a pillow and curl my hands under my chin. If I don’t have the pillow my arms will fall asleep from being bent too tightly.
I usually settle myself on my right side, with my right arm bent, hand on the pillow, under my cheek, and my left arm ‘draped’ across my stomach.
I sleep with my arms exposed and my hands under my pillow; the latter is because of my cat, who sees exposed fingers as a call to arms.
I have a stuffed turtle that I hug. Yeah, I’m a 33 year old woman who needs a stuffed animal to sleep.
Usually start to fall asleep on my right side. Right arm raised, under my pillow. Left arm usually around my dog. Unless he’s pissed at me for something and has gone to sleep at the foot of the bed.
I usually sleep on my stomach, with my arms sprawled out above my head. Think of a person who just jumped off of a building and is laying stomach down, face turned to the side, arms splayed out above/to the side of me. That’s what I look like.
I sleep on my side. One arm is curled under the pillow. the other is hugging either my girlfriend to me, or my body pillow, depending on if she’s staying the night, and which way I happen to be facing at the time.
When I’m sleeping on the couch, my arms are resting on my stomach, with one occasionally thrown over the arm of teh couch.
I rotate like an automobile axle! I go through more gyrations than a ballet dancer! I’m all over the bed, left, right, up and down.
Recently, I dislocated my shoulder, and this has put a nasty restriction on my sleeping positions! I’ll roll over, and shock myself awake with pain. Not fun!
But, once it heals, I go back to my Arthur Conan Doyle “Dancing Men” sleep postures!
Same here (33 in 3 weeks!) I have a large-sized Care Bear from 1984. My left arm goes around him with my hand near my face, and my right arm goes under the pillow. All of us are under the blankets.
I prefer to sleep on my left side with my arms folded in front of me, hands on the opposite upper arm, like I’m hugging myself lightly.
I like to sleep flat on my back, my arms straight at my sides.
Two different ways:
– On my side with a pillow between my legs. Arms under blankets when cold, out when warm.
– On my stomach with my arms at my sides close to my body and my hands palm up tucked under me, by my thighs and on each side of my crotch.
It’s cozy this way, try it 
I’d love to have pictures of everyone in their various postures…
One thing I do that I’m sure is unusual is fold my feet over each other. I was born with ridiculously floppy ankles and feet, so it’s completely comfortable for me to turn my feet 90 degrees inward and just sort of fold them over each other. I do it totally unconsciously.
I hereby ask for your hand in marriage. 
I hold another pillow, mainly for bodily support when I roll over onto my side.
I sleep on my stomach with my arms at my sides, covers up to my head. Excepting when I had the cast on my arm, which would have made it impossible. It took me two days to get used to sleeping on my right side, with the encasted arm over my head.
I’m like this until I’m settled. The position that actually lets me fall asleep varies from day to day. Once I am asleep though I don’t move again until morning.
The dogs have now figured this out and stay away from me until I stop moving at which point they drape themselves over any available limb and I wake up pinned to the bed by dog heads and paws.
As for arms, if I’m on my side they’re hugging a pillow, if I’m on my back it’s usually one over my stomach and one extended towards the middle of the bed and on my stomach I’m in the deadman pose that drewtoo99 described although my arms and hands are under the pile of pillows for warmth.
I start out on my left side, arms under covers, covers pulled up over my shoulder and tucked around my ear.
I lie on my side with one arm under one pillow, with another pillow over my head, held down with the other arm.
Yeah, I know.
I accept! Greatest love story of all time!
Me, too! I often wake up and find that my feet are on my pillow and my head is at the other end. I have no idea how I manage that in my bunk bed…