My ablutions ready me for sleep. They signal my internal body clock that sleep will happen soon.
Once I'm in bed, I start off on my back. Then both sides get slept on. Sometimes I awaken on my stomach (with sheet creases from the pillowcase, and dang, at my advanced age, those are hard to get rid of before noon), but more often than not I awaken on my right side.
I must have a limb out for temperature control until my body temp lowers enough for me to want all the covers. Flannel sheets saved my ass during the winter in California. They're a must-have for me now. I love sleeping on old, washedwashedwashedwashed silky high thread-count sheets in the summertime, especially if they're white. Can't sleep with socks on, except under extraordinarily cold circumstances. Nightshirts made out of modal and cotton feel best, but I'll sleep in only my undies if it's too warm. I don't mind white noise, but light has got to be blocked. One pillow; two if I have a cold or flu. Queen beds are great: enough room for two to be both intimate and comfortably apart.
A few years ago, I got the Beloved a body-length overstuffed pillow that she could snuggle with when I wasn't there--her artificial Sepia, you might say.
Later, I began putting the big pillow between us at night so that I wouldn't damage her with my flailing head and elbows. Evidently, I growl in my sleep.
These days, our puppy-monster takes on the role of giant-fluffy pillow:
Back in the early days of our relationship, my dearest had been used to sleeping alone. One time I moved slightly and startled him, and he threw his arms out to his sides (sort of like you do if there's a kid sitting next to you in the car and you have to slam on the brakes), and connected with my nose. Fortunately there wasn't a lot of force behind it as it was just an alarm reflex, but still, OW.
I sleep on a king size waterbed. Only one I've seen mentioned here! I sleep by myself and somehow manage to take up the whole bed. I can not sleep on my back. I sleep on either side or my stomach. When on my side, I have a pillow I put between my knees to keep my lower back from hurting. Don't know why, but it helps. I have to have a blanket or cover of some kind even when it's hot. I no longer require that every bit of me is covered, but most of me has to be. When it's really warm, one foot out can cool your whole body! Oh, and I don't snore or drool. Now, if I could figure out how to sleep longer than three hours at a time, or more than about five hours a night....
I had a king size waterbed right out of college, and sometime after marriage upgraded the mattress with the technology that kept improving on waterbeds. It was very comfortable. We changed it out for a convential bed when we moved out of the country for about 4 years, and never thought about getting another one, as they are somewhat of a hassle to set up, especially in a bedroom upstairs.
I sleep on a king size waterbed. Only one I've seen mentioned here! I sleep by myself and somehow manage to take up the whole bed. I can not sleep on my back. I sleep on either side or my stomach. When on my side, I have a pillow I put between my knees to keep my lower back from hurting. Don't know why, but it helps.
Speaking as one who is married to someone with chronic back/sleep problems who does the same thing, it helps because it keeps your legs and hips in a more neutral position, which in turn keeps your spine aligned rather than twisted.