I can't because it makes me snore and the sound or feeling of that wakes me up. I also remember reading that sleeping on your back gives you more intense dreams which seemed true when I was younger, before this snoring problem affected me.
Besides, the cat likes to lay on me at night and if I lay on my back he'd just step on my nuts and/or belly.>>2616
My dad had that, he even had to get a machine in his bedroom to keep him breathing regular. He went to one of those sleep clinics where you spend the night under diagnostic instruments and they said he went as long as 90 seconds without breathing.