Ours used to nip occasionally and it would cause a hand jerk reaction because it is so fast and surprising. But I realized it wasn’t really a bite. No blood drawn, just that instant realization of teeth on your skin after the fact, always caught me by surprise.
Hers were usually “move so I can squeeze in here” or “you are not done yet”. So there would be nips when petting. Apparently I ended up spoiling her with lengthy rubs and petting sessions. So if she thought I was cutting it short or I was cutting it short, as I pulled my hand away there would be a lightning quick nip followed by her immediately putting her head back down for more pets. Even if I wasn’t done petting her but just repositioning myself she took that as premature ending of rubs and would grab my hand as if to say, “Where do you think you are going? We’re not done.”
But because they weren’t painful bites I tolerated the nips for what they were. But I never could control the hand jerk away reflex. It was like a tendon reflex, uncontrollable.