probably lick his lips and then nose your hand, lick it and may attempt to nibble on the treat or toy.
keep your hand steady. your pup should eventually try to paw at it. it may take a few times, and you may have to grab his attention back from wherever it drifted off to. the moment he lifts his paw to meet your hand, either feed him a treat from your free hand, or if you have a clicker, click and give him the treat. it's very important that you do not let him have the treat in the high-five hand.
repeat the entire training process for about three blocks of 