Each of us co-slept to varying degrees but anytime our babies slept on or near us, we noticed how utterly uncomfortable we were. Once, Andy, a designer, thought of doing a birds-eye view, the ideas exploded out of our mouths.
Avoid lying on your stomach. If you are a stomach sleeper, it is likely that you will eventually complain of some neck pain because your neck will be rotated to the end of its available range.