Bite Me?

Last week during first period, one of my students announced that she had successfully passed her Road Test and was now the proud owner of a New Jersey Probationary Driver's License, and another girl turned to her and said, "Did you get somebody to bite it?" and I found this statement odd and said so, and she explained that it's good luck to get someone to bite your new driving license . . . but none of the other kids had heard of this tradition, nor had the students in the class next door . . . but I did find this reference to what must be a rather obscure practice, which may stem from biting a gold coin to tell if it's real (and the resultant Olympic tradition of biting your gold medal).