quite a funny question for your, as I couldn't find anything on the internet.
Everytime I scratch myself our 9 months neutered male cat stops whatever he's doing, points at me and will run towards my hand, sometimes nibbling it, some other times patting it, as if he's trying to scratch it without using claws. He doesn't actually hurt me nor it seems like he wants to, it looks like he can't understand the concept of a human scratching himself and is curious about it.
So much so that I sometimes do it on purpouse. Has anyone ever seen a similar behaviour with a cat?
And no, I don't scold him for that. It's just too funny.