What does the tail tooth mean in Japanese anime?

Tail tooth is the "end" of the business's one-year activities and the "first sound" of the people's Spring Festival activities. The first and fifteenth days of each month or the second and sixteenth days of each month are the days when Taiwanese businessmen worship the land god, which is called "tooth-making". February 2 is the first time to make teeth, called "head teeth"; 1February 16 The dentist was the last dentist, so it was called "tail tooth".

For example, eating tail teeth in Crayon Shinchan means having a reunion dinner.