where is your cat's bum when you sleep?

At the WellCat market stall during the week, someone talked to me about how, when they sleep, their cat is near their head — but always facing away from them, so the bum ends up right near their head.

We had a little chat about this, as I've also noticed that Skoda, one of my cats, always sleeps like this. My thought was that she sometimes gets annoyed because I'm always ruffling her head — because it's so cute. They thought it might be that the cat is protecting them, keeping an eye out for danger — a sign that they like and care for them.

I came home and did some searching for any scientific research or evidence on this behaviour... and came up empty. This is yet another behaviour we might notice in cats but still don't fully understand. Whether that's because it's not common, or just not important enough to have been studied, I'm not sure.

Where is your cat's bum when you sleep?