Mass ends only when the celebrant states, “The Mass is ended, go in peace,” and the congregation replies, “Thanks be to God.” If there is a recessional hymn, it is most polite to stay in the pew until the hymn is completed. If there is no hymn, the proper order of departure from the Mass first allows for the celebrant, concelebrant and assistances to descend from the Altar and proceed down the middle of the nave. It is only then, does the congregation begin to leave, starting with those in the front pews and followed by others in the successive pews. This order is important because upon leaving the pew, we are required to genuflect in the direction of the location of the tabernacle, where Christ’s true presence remains always. When one leaves the pew, one should not be confronted with people walking toward one as one genuflects!
For reasons which are not related to the historically rooted purpose of blessing oneself upon entering the Church, some parishioners sign themselves with Holy Water upon exiting the Church. It is fine to do this in terms of one’s piety, but it is not required that one do so. The blessing with Holy Water is for upon the entering of the Church, not the exiting.
Christ’s true presence remains in the tabernacle always and as a sign of fidelity and respect to our Savior and Redeemer, after Mass has ended, we should endeavor to leave the church in a quiet and reverent manner. This should also been done as a courtesy to those who have remained after Mass to pray!