A: Firstly, when it comes to the sacraments it is correct to say that the laity are generally not to imitate the words and gestures of the priest. Each have their proper role and function within the Mass.
However, the only thing I can think of that would pertain to the question being asked is our monthly blessing of those celebrating birthdays and anniversaries. This is not a celebration of the sacraments, but it is rather a sacramental. “[Sacramentals] are sacred signs which bear a resemblance to the sacraments.” (Catechism of the Catholic Church #1667)
“Sacramentals derive from the baptismal priesthood: every baptized person is called to be a ‘blessing’ and to bless. Hence lay people may preside at certain blessings; the more a blessing concerns ecclesial and sacramental life, the more is its administration reserved to the ordained ministry (bishops, priests, or deacons).” (CCC #1669) The Church gives permission for all the baptized to bestow blessings on others. “Among sacramentals blessings (of persons, meals, objects, and places) come first. Every blessing praises God and prays for his gifts.” (CCC #1671)
Therefore we should be blessing one another and praying for one another. This is why our bishop has asked us, in his recent pastoral letter Strength for our Families, to recognize couples celebrating anniversaries and support them with prayer.