Pudding, the last Sunday before Advent
“What is Stir-up Sunday?
It is a tradition that harks back to Victorian times when the family would gather together to stir the Christmas pudding five weeks before Christmas. The opening words of the Book Of Common Prayer, used on the last Sunday before Advent, reads: "Stir up, we beseech thee, O Lord, the wills of thy faithful people," so the tradition stands that this is the day to get stirring!”
... Christmas pudding would traditionally contain 13 ingredients to represent Jesus and his disciples.
It is traditionally stirred (while making a wish) by each member of the family from East to West, to remember the Wise Men that visited Jesus in the Nativity Story.”
(Source: https://www.goodhousekeeping.com/uk/christmas/christmas-countdown/a550045/ultimate-stir-up-sunday-when/)
