Silly but Interesting Question

[Rocky2022]

Why is it that when Rocky is on a surface, bed- tile- catbed-floor, he will scratch and scratch and scratch until he's comfy and goes to sleep. When Rocky is on me, he will scratch 1 time but more of a nuzzle?
I was thinking perhaps softness and/or heat...but if you look list above, some of these same characteristics would apply.

 

[xp29]

I'm guessing when he's on you he us maybe just trying to make sure his nails have a good grip so he doesn't slide in his sleep.