I taught my cats to stop clawing me when they kneaded just by teaching them the word "claws" (but since my GF was Peruvian, we used spanish to talk to the cats and it was "uñas").

All I did was bring their claws out a little, rub my finger across the tips so that my fingerprint vibrated the claws (to draw their attention there) then said "uñas". And repeated it.

Then when we'd be cuddling they'd be kneading and if they started including their claws in the kneading I'd just say "uñas" and they'd retract their claws and keep kneading.

No operant conditioning required. I used a little classical conditioning to teach them the word, then mere mention of the word was enough because they already knew the claws were uncomfortable to other people. They were just extending their claws unconsciously while kneading.