As that is the last day of the year, New Year's Eve sounds very busy. "Shiwasu" is another name of December in Japanese and that means "even teachers run". Teachers in this case can be thought as priests who usually don't move so much. However, as it is the last month of the year, even priests become really busy and have to run. Although I am not a priest, I run too, especially on New Year's Eve, to prepare the special dishes called Osechi ryori that is eaten on New Year's Day.