I get into the most exciting positions during sleep. Sometimes I wake up with my arms numb because I've somehow been sleeping on my stomach with my head tilted to the side, arms crossed under the pillow so my upper body weighs them down. But usually when I go to sleep I'm on my side, or if I'm having troubles falling asleep I'll lie on my back and stare at the roof.
Man, I feel like I could endlessly talk about this.
Hahah, took the time to read through all of these.
For me it's left/right, whatever is more comfortable that night, and in a "fetal" position, and i've just started using a pillow parallel to my body with 1 hand/forearm under it.
I usually try to stay on my back or my stomach so that my neck isn't strained, or else I wake up with headaches. Most of the time I'm on my stomach with a pillow on my legs or in between them and my hands/arms underneath the pillow that I'm laying my head on.