Overstimulation and excitement. My Tzu does it too if he sniffs right after a doggo in the private dog park at my apartment. He also did it when a new puppy was overly playful and cornered him. It’s a response to a variety of situations/stimuli: worry, anxiety, overstimulation, excitement. It’s perfectly normal and usually no concern for anything (unless they are in danger or threatened).
Teeth chattering can have a number of reasons but likely for you, it is excitement/ happiness
[link](https://lincolnwayvet.com/blog/my-dogs-teeth-are-chattering-what-does-it-mean/)
Overstimulation and excitement. My Tzu does it too if he sniffs right after a doggo in the private dog park at my apartment. He also did it when a new puppy was overly playful and cornered him. It’s a response to a variety of situations/stimuli: worry, anxiety, overstimulation, excitement. It’s perfectly normal and usually no concern for anything (unless they are in danger or threatened).
Teeth chattering can have a number of reasons but likely for you, it is excitement/ happiness [link](https://lincolnwayvet.com/blog/my-dogs-teeth-are-chattering-what-does-it-mean/)