I keep hurting myself. I have developed a style of sleeping on my stomach with my arm underneath my chest, with my hand reaching to my face. This often makes my hand fall asleep, but more annoying, if I have a dream with a physiological response, I may hurt myself with my hand.
See, the hand typically rests with the fingertips just below my lips. A few times in recent months, I have awakened to discover little sore spots on the inside of my lip. I was somewhat worried about them until I went to bed in my customary position and discovered that my fingertips were placed exactly where they could cause the sore. Apparently, if I have a dream that makes me clench my fist, I will dig into face and cut the inside of my mouth with my teeth.
The moral of the story, obviously, is that my hands make it dangerous for me to sleep with myself.