How come if I let my dog lick my hand he bites at it? [Discussion]

I just think it is really interesting how my dog licked and bit at my hand, if I let him like I did just now for like 5 minutes, just out of curiosity. He began by licking my hand, and licking it essentially the whole time while slowly beginning to nip at it it, gently, and began biting more and more and nibbling at my fingers.Why dogs do this? Like is he sensing me, squaring me up, or actually thinking he is going to eat me. via /r/dogs http://ift.tt/2qKDPjm