I prefer sleeping on my left side most of the time, but this has me facing a wall. I have developed a psychological trick to mitigate my imagination of monsters sneaking in behind my back though: Imagine a pulsing protective dome around you, invisible to you on the inside, that blocks the monsters both physically and audibly outside of the barrier. This way I can safely imagine all the monsters I want, but they stay outside that barrier, so do not worry me at all and end up feeling safe. Being also a family man with kids and dogs in separate rooms, I do a mental excersise where I put up a shield over each of their sleeping places. This way I do not have to fear for their sakes either. If I have to go to the bathroom & kids rooms etc in the dark, especially if I have watched a late night horror film that has left me creeped out, I imagine being surrounded by a high current field that will zap anything that gets close. It usually helps to uust keep imagining a buzzing high voltage sound in my ears. Here are some tricks for anybody struggling with overly active imaginations.