There are several traditions associated with the pudding. One is that it is made on "Stir Up Sunday", the Sunday five weeks before Christmas, at which the following prayer is read:
Stir up, we beseech thee, O Lord, the wills of thy faithful people; that they, plenteously bringing forth the fruit of good works, may by thee be plenteously rewarded; through Jesus Christ our Lord. Amen
Another tradition is that everyone in the household (especially children) stirs the pudding mixture and makes a wish. It is also traditional to include a silver sixpence in the mixture, and whoever gets the sixpence in their portion on Christmas day gets to be "king" for the day, and all their requests must be fulfilled.