And other Catholics could surely add innumerable other [Catholic practices]: some silly, some profound, some a source of comfort, others the source of light-hearted humor. Catholic practices make up the daily life of a Catholic individual and a Catholic society. The morning offering, the invocation of Jesus, Mary and Joseph, the sprinkling of holy water on children at bedtime, the incantation to Saint Anthony ("Tony, Tony, come around; something's lost and can't be found"), the pleas to Saint Jude to prevent a bankruptcy, the novenas for a sick spouse. All of these many practices fill the lives of the faithful, enrich, comfort and orient them. Often it is difficult to trace their origin. Often the ones which seem most intimate and natural to a people were never even introduced by ecclesiastical authority. They emerged as natural, faith-filled expressions of love or joy or thanksgiving or grief or desperation.

The one characteristic these Catholic practices all seem to share is their ability to turn people away from the mundane, the worldly, the everyday, and direct them toward the sacred, the transcendent, the eternal. One could be travelling on the streetcar in Pittsburgh thinking about how to make new sales contacts or how to position oneself to meet the new girl in the office when suddenly, on the part of a half-dozen people, there was an adverting to another reality, another dimension, not separate from this realm, but permeating it, leavening it, making sense of it. Perhaps the adverting to Our Lord in the Blessed Sacrament by those on the street car was only fleeting, with virtually no break in the train of thought regarding increasing sales or meeting the new girl. But the adverting took place; Our Lord was acknowledged; and implicitly at least, the statement was made that increased sales was no end in itself and any future wife would, one would hope, be married in the Lord.

Below are instructions on some of these ways of "adverting to Our Lord" by the use of posture and gesture...

Bow of the head (or "simple bow")

How:

Simply lower your chin toward your throat and hold a moment

When:

• When you pass by a Church, bow your head and make the Sign of the Cross to honor the Real Presence of Christ in the tabernacle.
  
  
• Any time you hear or say the Holy Name "Jesus" (note that "Christ" is His title, meaning "Annointed One"; there is no need to bow the head at just the mention of the word "Christ"). Men should remove their hats and bow their heads when passing a church or when His Name is spoken; this practice is for both inside and outside of Mass. All Catholics bow their heads at these times (yes, if you're having a casual conversation with someone on the subway and you pass a church or mention His Name, you actually are supposed to bow your head, removing your hat if you are a man). ¹
  
  
• Before Mass: when the priest and Crucifer (the acolyte bearing the Cross) walk down the aisle
  
  During Mass: any time you hear "Father, Son, and Holy Ghost (or "Holy Spirit")" mentioned together, or any time you hear the word "Trinity"; when hearing the name of Mary; and when hearing the name of the Saint in whose honor the Mass is being celebrated.
  
  After Mass: as the priest leaves the Altar (some make a profound bow). It is also customary to pray for him at this time.
  
  

Striking of the Breast

How:

With either a fist or with the tips of the fingers, held close together, strike your chest over the heart to express regret and sorrow²

When:

• at the Mass, formally: at each "mea culpa" during the Confiteor; at the Nobis Quoque Peccatoribus (priest); three times during the Agnus Dei; and three times during the Domine, Non Sum Dignus
  
  
• informally, at the "forgive us our trespasses" ("dimitte nobis debita nostra") in the "Our Father"
  
  
• informally, any time to express penitence or remorse inside or outside of the Liturgy
  
  
• informally, when the bells are rung at Consecration and the Host or Chalice are raised, bow the head and strike the breast three times. The mental prayer at this moment should be, "My Lord and my God."
  
  

Bow at the waist (or "profound bow")

How:

Bow at the waist in the manner of the Japanese (about 30^o forward)

When:

• at the Aspérges at Mass when the priest sprinkles the congregation with holy water
  
  
• when the Altar boy incenses the congregation during the Mass
  
  
• Cross yourself and make a profound bow when the priest and Crucifer walk down the aisle before and after Mass. After Mass, as the priest leaves the Altar, it is also customary to pray for him. (Some simply bow the head instead of making a profound bow at these times)
  
  
• when greeting a hierarch who doesn't have jurisdiction over you (e.g., the Bishop of a diocese other than one in which you live). As you bow, kiss the hierarch's ring. This bow and ring-kissing are only done if the Pope is not present.
  
  

Genuflection on Left Knee

How:

When:

• When greeting or leaving the Pope or other hierarchs with the rank of Bishop or above and who have jurisdiction over you (only when the Pope is not present) -- e.g., to the Bishop or Archbishop of your diocese, not of a neighboring diocese. During the left-knee genuflection, a kiss is given to the hierarch's ring. Then stand. This honor is being shown to their office, not to them as persons.

Genuflection on Right Knee

How:

Looking at what you are genuflecting toward, kneel on your right knee for a moment in the manner of a man proposing to a woman, bringing the right knee all the way to the floor, close to the heel of the left foot, keeping the back and neck erect. Hold for a moment, then stand.

When:

• Genuflect toward the Tabernacle where the Blessed Sacrament is reserved, and each time you pass in front of it (except when you're in procession, such as standing in line for Communion, or returning to your seat afterward). While this should, on one level, be a matter of habit, it shouldn't be done thoughtlessly. Remind yourself when genuflecting toward the Tabernacle that you are kneeling before God. Praying mentally, "My Lord and My God" is a good habit to get into while genuflecting on the right knee. If the Tabernacle is not on the Altar, genuflect toward the Altar and the Altar Crucifix.
  
  
• Before a relic of the True Cross when it is exposed for public adoration.
  
  
• On Good Friday to Holy Saturday, after the ceremony of the Adoration of the Cross, genuflect when passing in front of the exposed Crucifix on the Altar.
  
  
• Before entering or after exiting your pew at church, while facing toward Christ in the tabernacle.
  
  

Kneeling (Double Genuflection)

How:

Kneel on both knees

When:

• any time the Blessed Sacrament is exposed, to show adoration and humility
  
  
• many times during the Mass: during the Prayers at the Foot of the Altar, after the Sanctus, after the Agnus Dei, at the altar rail when receiving Communion, and at the Last Blessing
  
  
• during Confession, inside or, in emergencies, outside of the Confessional
  
  
• when receiving a priestly blessing, inside or outside of the Liturgy. If you are unable for some reason to kneel, then bow your head.
  
  
• during private prayer (see St. Dominic's "Fourth Way"" of prayer)
  
  

Prostration

How:

Keeping your legs together, drop to your knees and then lie down flat on the floor on your face, crossing your hands underneath your forehead forming a "pillow" on which to rest your forehead 

When:

• Prostrations, which signify total humility and penance, are made during the Rite of Ordination, during rites of religious profession (i.e., entry into religious orders), as penance in religious orders, and by anyone during private prayer before a Crucifix or the Blessed Sacrament. It is also occasionally made by adults, at the priest's invitation, before the Profession of Faith in the solemn Rite of Baptism. (See St. Dominic's "Second Way" of prayer)

Kisses

How:

To paraphrase Lauren Bacall in "To Have and Have Not," you know how to kiss, don't you? You just put your lips together... but don't blow.

When:

• Kissing Crucifixes and Icons (2-D or 3-D): In icons that depict more than one person, kiss first Our Lord (His Feet, Hem of His garment, or hands), then Our Lady (her hands or veil), then the angels and Saints. To reverence a Crucifix or icon that you can't reach too well with your lips, kiss your fingers and then touch where you would kiss.
  
  
• Many Catholics kiss the Bible before opening and reading.
  
  
• Kissing rings of Bishops and Popes: see above under "Genuflection on Left Knee." The kissing of rings ("baciamano") is to honor the office the ring-wearer holds, not their person. The Pope's ring -- called “the fisherman’s ring” -- has been used as far back as the 13th century. The signet on the ring was used as a seal to press into wax used to enclose papal documents. Each Pope has his own ring, which is destroyed after his death.
  
  
• Kissing a priest's hands (literally "baciamano"): the priest's hands may be kissed when greeting or leaving him because they alone are able to confect the Holy Eucharist. This is an honor being shown to Holy Orders, not to them as persons. Priests' hands are also kissed on Palm Sunday when receiving a palm (which is also kissed). During the Mass, the priest's hands are kissed by the acolytes/altar boys.
  
  

Orans

How:

Raise arms either at your sides and with hands up to shoulder height, or raise arms up over your head as a child would when wanting his father to pick him up

When:

• Priests perform this gesture (the first method mentioned) during the Mass.
  
  
• Laymen sometimes adopt this position during private prayer. It should not be used by laymen at the Mass. (See St. Dominic's "Seventh Way" of prayer) ³

Also, see the special page on the Sign of the Cross which will teach you about the different Signs of the Cross and when, where, and how they are made.

For more information on when to kneel, etc., during Mass, see the Order of the Mass page. For an interesting work that shows how St. Dominic used posture in prayer, see "The Nine Ways of Prayer of St. Dominic."

Footnotes:
¹ The custom of bowing the head at the mention of His Name was formally written into law at the Second Council of Lyons, A.D. 1274, convened by Pope Gregory X: "Those who assemble in church should extol with an act of special reverence that Name which is above every Name, than which no other under Heaven has been given to people, in which believers must be saved, the Name, that is, of Jesus Christ, Who will save His people from their sins. Each should fulfil in himself that which is written for all, that at the Name of Jesus every knee should bow; whenever that glorious Name is recalled, especially during the sacred Mysteries of the Mass, everyone should bow the knees of his heart, which he can do even by a bow of his head."

A religious Sister told me once that "back in the day," Catholic schoolkids  would sometimes make a game of saying Our Lord's Name as often as they could in order to force their teaching Sisters to bow their heads. Apparently, getting the nuns' heads bobbing up and down was a sport for the mischievous wee ones.  

² The Catholic Encyclopedia cites St. Augustine (A.D. 354-430) as saying in his Sermo de verbis Domini, "No sooner have you heard the word 'Confiteor' than you strike your breast. What does this mean except that you wish to bring to light what is concealed in the breast, and by this act to cleanse your hidden sins?"

It also cites St. Jerome (ca. A.D. 340-420) as saying in Ezechiel, c. xviii, "We strike our breast because the breast is the seat of evil thoughts: we wish to dispel these thoughts, we wish to purify our hearts."

³ The orans position is frequently depicted in the art of the Catacombs where figures praying in this manner represented departed souls praying for the soul of the one whose tomb the figures adorn. The Catholic Encyclopedia says, "Numerous Biblical figures, for instance, depicted in the catacombs—Noah, Abraham, Isaac, the Three Children in the Fiery Furnace, Daniel in the lions' den—are pictured asking the Lord to deliver the soul of the person on whose tombs they are depicted as He once delivered the particular personage represented." It goes on to say that in addition to the Biblical Orans figures, there are idealized figures in that "ancient attitude of prayer" which symbolize the soul of the entombed one in heaven, praying for its friends on earth. "This symbolic meaning accounts for the fact that the great majority of the figures are female, even when depicted on the tombs of men."