So cool - my tooth fairy would have left a note stating that biting people is usually not the way teeth come out to please next time just ask an adult kindly for help pulling it out.
Something that is not judgemental but acknowleding that there is a better way.
"Oh cool! Another tooth out!! I was so surprised when I heard that it was found on someone's arm. How did that happen? Did you really bite someone? You know, the best way to get loose teeth out is to ask an adult for help. No more biting, o.k.? Anyway, congratulations and here is $1, the going rate for teeth tonight. Have a great day!"