Traditionally this is prayed 15 times each day from November 30th, the feast of St. Andrew, through Christmas Day.
Hail, and blessed be the hour and moment at which the Son of God was born of a most pure Virgin at midnight in Bethlehem in the piercing cold. At that hour vouchsafe, O my God, to hear my prayers and grant my desires.
(Mention your intentions here)
Through Jesus Christ and His most Blessed Mother.
Amen.