When you're constipated and unable too poop I was told that you should lay on your left side to help you poop.
Laying on your left side when constipated helps food waste move more freely through the large intestine and into the lower colon.
Also when you sleep on your left side your pancreas and stomach will hang more naturally because our stomach lies on the left side of our body.
I found sleeping on my left side to help me poop when I was constipated. I didn't believe it at first when a friend told me to try it but it worked.