This is a simple hack/project.
We recently got a new puppy who loves to play. To a dog, the mouth is a hand. It's what he or she uses to pick up things and explore the world. When they play with other dogs, they grab with their mouths and learn not to "bite" too hard. However, our little guy is tiny and has sharp hypodermic-like teeth. Despite his best attempts to keep his mouth open and play nice, my hands were too big and constantly getting scraped.
This led me to create these puppy teething puppets. I picked up a cheap pair of sturdy leather work gloves. Using a Sharpie, I decorated them with some terrifying monsters. Now when it comes to play time, my hands are protected.
Thanks to the magic of operant conditioning (behavior/reward and negative reinforcement), our puppy has learned to not bite ungloved hands and to get ready for some fun activity when the gloves are on.
Step 1: Okay, I'll Spell It Out.
My puppy liked to play with plain leather gloves. However, with the "scary" faces, he really gets into the role playing.
You will need at least one leather glove and a black Sharpie marker. Use your imagination and draw a scary face on at least one side of the glove. It is a puppet, so use the fingers creatively. My first monster has hair on the fingers (his hair ripples as he prepares to attack). My second monster has eye stalks on the fingers, which makes him more vulnerable to puppy attack.
Step 2: Step 2: Be Consistent in Training Your Dog!
It's a puppet, so throw yourself into the role of a monster. Our puppy likes to sneak up on the monster and loves it when his attack leaves the monster flopping on the ground.
Establish ground rules. Allow only rough play when the glove is on. Cease interacting and use a verbal "no" if your pup attempts to bite an ungloved hand. Be consistent in your feedback and your pup will love you.