88. When the distribution of Communion is over, if appropriate, the Priest and faithful pray quietly for some time. If desired, a Psalm or other canticle of praise or a hymn may also be sung by the whole congregation.
Two good points here. I can’t imagine an ordinary situation when “some time” for silence wouldn’t be appropriate. I’m very sympathetic to the need for silence at liturgy. I think those moments are better cultivated at the core moments of the Mass, and after Communion is one of them. Silence then becomes part of the innermost fabric of prayer, for both the individuals and the community as a whole. I’m more of a skeptic for the need for absolute silence before Mass, when it can be miscommunicated that silence is the only way to prepare for Mass, or that the introductory rites can take on a more perfunctory role, or that the one-stop shopping mentality of the culture is imposed on a weekly visit to Church. That said, if a community’s style is quietude before Mass, it should be cultivated from within, not without. There’s also nothing wrong with encouraging people to pray quietly on their own time.
The post-Communion hymn of praise is a good idea. After the silence. Before the post-Communion prayer. I think the prescription of GIRM 86 should be taken into account whenever an assembly doesn’t sing (whether it be by their choice or the music director’s). Spiritual union, gladness of heart, a sense of community: these are the values attributed to the Communion song in GIRM 86. They should be cultivated somewhere, somehow. This would happen before the presider’s prayer, not after it.
The Communion Rite concludes with the presider’s prayer:
89. To bring to completion the prayer of the People of God, and also to conclude the whole Communion Rite, the Priest pronounces the Prayer after Communion, in which he prays for the fruits of the mystery just celebrated.
At Mass a single Prayer after Communion is said, and it ends with the shorter conclusion; that is:
• if the prayer is directed to the Father: Through Christ our Lord;
• if it is directed to the Father, but the Son is mentioned at the end: Who lives and reigns for ever and ever;
• if it is directed to the Son: Who live and reign for ever and ever.
The people make the prayer their own by means of the acclamation Amen.
Note that this is not a closing prayer.