At the Gloria in Excelsis, the celebrant alone, facing the altar, intones Glory be to God on high, with hands held apart, and rejoins them palm to palm while the congregation replies, and on earth good will toward men. His hands remain palm to palm throughout the remainder of the Gloria. The celebrant and attendants are careful to bow at the usual places during the Gloria ("we worship Thee," "we give thanks to Thee for Thy great glory," "Jesus Christ," "receive our prayer," and "Thou only, O Christ, with the Holy Ghost, art + most high in the glory of God the Father").
The Gloria is not said at low (spoken) mass, nor during penitential seasons; though some permit its use in Advent. It is also sung on Maundy Thursday.
The substitution of "This is the Feast" for the Gloria is a most unfortunate innovation.