It depends on the bed actually. Cause I prefer to lie on my side closest to the outer edge that faces the room. At least until my ear starts hurting/getting uncomfortable, then I switch sides.
But also if it's very noisy around me, then I'll lie on my right side cause I'm deaf on my left ear so that muffles out most surrounding sounds if I don't have ear plugs. And if I want to listen to music instead, then I prefer lying on my left side so I can hear it.
So, I picked the option "rolling around" even though I do have various reasons for picking one or the other side.
For shorter times I sometimes lie on my back, but still have my head to either side. Can't lie on my stomach, it hurts my neck too much.