My DS does the same thing but we call it "starfish paws" . We had a cat who liked to knead us like a piece of dough and then start sucking on your clothes (maybe she was weaned too early!). And this is what it reminds me of. Anyways I think its cute and we just keep his nails short.
My tom cat was weaned too early and used to suck on my lady kitty. Now he just sucks on himself, and kneads himself. He is indeed a freak.
“Only with trust, faith, and support can the woman allow the birth experience to enlighten and empower her.” - Annie Kennedy & Penny Simkin