Many rituals that your parents may have performed or your parochial schoolteachers insisted on when you walked into sacred space fall under the heading of personal pieties. Enter any city church and you’re likely to see a host of ethnically rooted expressions of faith: people kissing statues, moving up the aisles on their knees, leaving rosaries around the necks of madonnas or handwritten prayers rubber-banded to the hands of Jesus. Dollar bills origami-ed into the shape of hearts are becoming popular in the candle offering box, too.

While these practices are meaningful to their practitioners, they are not "officially" Catholic gestures. Blessing yourself—that is, making the Sign of the Cross “in the name of the Father, and of the Son, and of the Holy Spirit”—is, however, a formal ritual gesture of the church. It marks you as a Christian, and it is the way both public Catholic prayer begins as it is for the most personal expression of thanks before and after meals. It also reminds Christians of their belief in three “persons” in one God.

The full Sign of the Cross includes touching the forehead, heart, and both shoulders, signifying acceptance of the demands of discipleship over our thoughts, desires, and deeds. A smaller version, performed before the proclamation of the gospel at Mass, involves making a thumb sketch of the cross on the forehead, lips, and heart while praying silently, “May the Lord be on my mind, on my lips, and in my heart, that I may be worthy to proclaim the gospel.” At the start of Lent, it’s also customary to bear the Sign of the Cross in ashes on the forehead.

Genuflection, or touching down one knee accompanied by the Sign of the Cross, is a particular gesture made only in a Catholic church or other place designated for worship. It’s a sign of reverence toward the real presence of Christ in the Eucharist. Sometimes the reverence is directed toward the table of the Lord (the altar) if Mass is to be celebrated. Otherwise, genuflection is to be directed toward the tabernacle, where the real presence remains in the consecrated hosts. For those who cannot genuflect, a simple bow is sufficient. These movements are not magical but reminders that we are incarnate beings who believe in a God who chose to become a Word made flesh.

Scripture
Matthew 28:19; Romans 6:12-14; 12:1; 1 Corinthians 10:16-17

Website
Questions and answers about Catholic “sacramentals”—the Sign of the Cross, medals, and others

Books
Why Do Catholics Do That? by Kevin Orlin Johnson (Ballantine Books, 1994)
Catholic Etiquette: What You Need to Know About Catholic Rites and Wrongs by Kay Lynn Isca (Our Sunday Visitor, 1997)
Now That You Are a Catholic: An Informal Guide to Catholic Customs, Traditions, and Practices by John J. Kenny, C.S.P. (Paulist Press, 2003)