Why sleep on back?

Why do people always say to sleep on your back when attempting WILD? It feels harder to breathe when I lie on my back, is that normal? I just don’t see the need to sleep on my back for WILD.

um…i dont know i guess you dont have to

Some people can’t WILD unless they sleep on their backs, some people can’t WILD. It is more important to sleep comfortably then to sleep on your back. I lay on my side when I WILD. Do what works for you.
don

I find that if I sleep on my back the SP and sleep onset comes quicker thus making WILD faster and easier.