German shepherd/Beagle mix - too rough

I have a 13 week old Beagle/German Shepherd who is the love of my life. He just gets too rough when he's excited and it takes a lot to calm him down. He used to nibble, but it's gotten to the point where, when he's playing ONLY, he bites too hard or is too difficult to calm down. I've tried to use bitter things on my hands to keep him from biting, but it also makes it a challenge for him to get to my hands. He gets walked regularly and played with multiple times per day, but he's just a handful when he's really hyper.

Any help?

Some of it is his age, he's just a puppy and still learning. When he even nips at you hands, "yelp" and pull your hands up where he cannot get them, and turn your back on him until he calms down. It make take many repetitions, but he will come to realize that when his teeth make contact with you, playtime ends, and so he's stop that behavior. Just make sure everyone in the house understand this, and is consistent. Pups chomp on each other in play all the time, but they ned to learn that's not acceptable with the humans, we don't have fur to help protect ourselves from those sharp teeth!