Chapter IV-D. Some General Rules for All Forms of Mass
Veneration of the Altar and the Book of the Gospels
232. According to traditional liturgical practice, the altar and the Book of the Gospels are kissed as a sign of veneration. But if this sign of reverence is not in harmony with the traditions or the culture of the region, the conference of bishops may substitute some other sign, after informing the Apostolic See.
Genuflections and Bows
233. Three genuflections are made during the Mass: after the showing of the eucharistic bread, after the showing of the chalice, and before communion.
If there is a tabernacle with the blessed sacrament in the sanctuary, a genuflection is made before and after Mass and whenever anyone passes in front of the Blessed Sacrament.
234. There are two kinds of bow, a bow of the head and a bow of the body:
a) A bow of the head is made when the three divine Persons are named together and at the name of Jesus, Mary and the saint in whose honor Mass is celebrated.
b) A bow of the body, or profound bow, is made: toward the altar if there is no tabernacle with the Blessed Sacrament; during the prayers, Almighty God, cleanse and Lord God, we ask You to receive; within the profession of faith at the words, by the power of the Holy Spirit; in Eucharistic Prayer I (Roman Canon) at the words, Almighty God, we pray. The same kind of bow is made by the deacon when he asks the blessing before the gospel. In addition, the priest bends over slightly as he says the words of the Lord at the consecration.
234. The use of incense is optional in any form of Mass:
a) during the entrance procession;
b) at the beginning of Mass, to incense the altar;
c) at the procession and proclamation of the gospel;
d) at the preparation of the gifts, to incense them, as well as the altar, priest, and people;
e) at the showing of the eucharistic bread and chalice after the consecration.
236. The priest puts the incense in the censer and blesses it with the sign of the cross, saying nothing.
This is the way to incense the altar:
a) If the altar is freestanding, the priest incenses it as he walks around it.
b) If the altar is not freestanding, he incenses it while walking first to the right side, then to the left.
If there is a cross on or beside the altar, he incenses it before he incenses the altar. If the cross is behind the altar, the priest incenses it when he passes in front of it.
237. Whenever a particle of the eucharistic bread adheres to his fingers, especially after the breaking of the bread or the communion of the people, the priest cleanses his fingers over the paten or, if necessary, washes them. He also gathers any particles that may fall outside the paten.
238. The vessels are purified by the priest or else by the deacon or acolyte after the communion or after Mass, if possible at a side table. Wine and water or water alone are used for the purification of the chalice, then drunk by the one who purifies it. The paten is usually to be wiped with the purificator.
239. If the eucharistic bread or any particle of it should fall, it is to be picked up reverently. If any of the precious blood spills, the area should be washed and the water poured into the sacrarium.
Communion Under Both Kinds
240. Holy Communion has a more complete form as a sign when it is received under both kinds. For in this manner of reception a fuller light shines on the sign of the eucharistic banquet. Moreover there is a clearer expression of that will by which the new and everlasting covenant is ratified in the blood of the Lord and of the relationship of the eucharistic banquet to the eschatological banquet in the Father's kingdom. 
241. For the faithful who take part in the rite or are present at it, pastors should take care to call to mind as clearly as possible Catholic teaching according to the Council of Trent on the manner of communion. Above all they should instruct the people that according to Catholic faith Christ, whole and entire, as well as the true sacrament are received even under one kind only; that, therefore, as far as the effects are concerned, those who receive in this manner are not deprived of any grace necessary for salvation. 
Pastors are also to teach that the Church has power in its stewardship of the sacraments, provided their substance remains intact. The Church may make those rules and changes that, in view of the different conditions, times, and places, it decides to be in the interest of reverence for the sacraments or the well-being of the recipients.  At the same time the faithful should be guided toward a desire to take part more intensely in a sacred rite in which the sign of the eucharistic meal stands out more explicitly.
242. At the discretion of the Ordinary and after the prerequisite catechesis, communion from the chalice is permitted in the case of: 
1. newly baptized adults at the Mass following their baptism; adults at the Mass at which they receive confirmation; baptized persons who are being received into full communion of the Church;
2. the bride and bridegroom at their wedding Mass;
3. deacons at the Mass of their ordination;
4. an abbess at the Mass in which she is blessed; those consecrated to a life of virginity at the Mass of their consecration; professed religious, their relatives, friends, and the other members of their community at the Mass of first or perpetual vows or renewal of vows;
5. those who receive institution for a certain ministry at the Mass of their institution; lay missionary helpers at the Mass in which they publicly receive their mission; others at the Mass in which they receive an ecclesiastical mission;
6. the sick person and all present at the time viaticum is to be administered when Mass is celebrated in the sick person's home;
7. the deacon and ministers who exercise their office at Mass;
8. when there is a concelebration, in the case of:
a) all who exercise a liturgical function at this concelebration and also all seminarians present;
b) in their churches or oratories, all members of institutes professing the evangelical counsels and other societies whose members dedicate themselves to God by religious vows or by an offering or promise; also all those who reside in the houses of members of such institutes and societies;
9. priests who are present at major celebrations and are not able to celebrate or concelebrate;
10. all who make a retreat at a Mass in which they actively participate and which is specially celebrated for the group; also all who take part in the meeting of any pastoral body at a Mass they celebrate as a group;
11. those listed in nos. 2 and 4, at Masses celebrating their jubilees;
12. godparents, relatives, wife or husband, and lay catechists of newly baptized adults at the Mass of their initiation;
13. relatives, friends, and special benefactors who take part in the Mass of a newly ordained priest;
14. members of communities at the conventual or community Mass, in accord with the provisions of this Instruction, no. 76.
Further, the conferences of bishops have the power to decide to what extent and under what considerations and conditions Ordinaries may allow communion under both kinds in other instances that are of special significance in the spiritual life of any community or group of the faithful.
Within such limits, Ordinaries may designate the particular instances, but on condition that they grant permission not indiscriminately but for clearly defined celebrations and that they point out matters for caution. They are also to exclude occassions when there will be a large number of communicants. The groups receiving this permission must also be specific, well-ordered, and homogeneous.
243. Preparations for giving communion under both kinds:
a) If communion is received from the chalice with a tube, silver tubes are needed for the celebrant and each communicant. There should also be a container of water for purifying the tubes and a paten on which to put them afterwards.
b) If communion is given with a spoon, only one spoon is necessary.
c) If communion is given by intinction, care is to be taken that the eucharistic bread is not too thin or too small, but a little thicker than usual so that after being partly dipped into the precious blood it can still easily be given to the communicant.
1. Rite of Communion under Both Kinds Directly from the Chalice
244. If there is a deacon or another assisting priest or an acolyte:
a) The celebrant receives the Lord's body and blood as usual, making sure enough remains in the chalice for the other communicants. He wipes the outside of the chalice with a purificator.
b) The priest gives the chalice with the purificator to the minister and himself takes the paten or ciborium with the hosts; then both station themselves conveniently for the communion of the people.
c) The communicants approach, make the proper reverence, and stand in front of the priest. Showing the host he says: The body of Christ. The communicant answers: Amen, and receives the body of Christ from the priest.
d) The communicant then moves to the minister of the chalice and stands before him. The minister says: The blood of Christ, the communicant answers: Amen, and the minister holds out the chalice with purificator. For the sake of convenience, communicants may raise the chalice to their mouth themselves. Holding the purificator under the mouth with one hand, they drink a little from the chalice, taking care not to spill it, and then return to their place. The minister wipes the outside of the chalice with the purificator.
e) The minister places the chalice on the altar after all who are receiving under both kinds have drunk from it. If there are others who are not receiving communion under both kinds, the priest gives these communion, then returns to the altar. The priest or minister drinks whatever remains in the chalice and carries out the usual purifications.
245. If there is no deacon, other priest, or acolyte:
a) The priest receives the Lord's body and blood as usual, making sure enough remains in the chalice for the other communicants. He wipes the outside of the chalice with the purificator.
b) The priest then stations himself conveniently for communion and distributes the body of Christ in the usual way to all who are receiving under both kinds. The communicants approach, make the proper reverence, and stand in front of the priest. After receiving the body of Christ they step back a little.
c) After all have received, the celebrant places the ciborium on the altar and takes the chalice with the purificator. All those receiving from the chalice come forward again and stand in front of the priest. He says: The blood of christ, the communicant answers: Amen, and the priest presents the chalice with purificator. The communicants hold the purificator under their mouth with one hand, taking care that none of the precious blood is spilled, drink a little from the chalice, and then return to their place. The priest wipes the outside of the chalice with he purificator.
d) After the communion from the chalice, the priest places it on the altar and if there are others receiving under one kind only, he gives them communion in the usual way, then returns to the altar. He drinks whatever remains in the chalice and carries out the usual purifications.
2. Rite of Communion under Both Kinds by Intinction
246. If there is a deacon, another priest assisting, or an acolyte present:
a) The priest hands the minister the chalice with purificator and he himself takes the paten or ciborium with the hosts. The priest and the minister of the chalice station themselves conveniently for distributing communion.
b) The communicants approach, make the proper reverence, stand in front of the priest, and hold the communion plate below their chin. The celebrant dips a particle into the chalice and, showing it, says: The body and blood of Christ. The communicants respond: Amen, receive communion from the priest, and return to their place.
c) The communion of those who do not receive under both kinds and the rest of the rite take place as already described.
247. If there is no deacon, assisting priest, or acolyte present:
a) After drinking the blood of the Lord, the priest takes the ciborium, or paten with the hosts, between the index and middle fingers of one hand and holds the chalice between the thumb and index finger of the same hand. Then he stations himself conveniently for communion.
b) The communicants approach, make the proper reverence, stand in front of the priest, and hold a plate beneath their chin. The priest takes a particle, dips it into the chalice, and, showing it, says: The body and blood of Christ. The communicants respond: Amen, receive communion from the priest, and return to their place.
c) It is also permitted to place a small table covered with a cloth and corporal at a suitable place. The priest places the chalice or ciborium on the table in order to make the distribution of communion easier.
d) The communion of those who do not receive under both kinds, the consumption of the blood remaining in the chalice, and the purifications take place as already described.
3. Rite of Communion under Both Kinds Using a Tube
248. In this case the priest celebrant also uses a tube when receiving the blood of the Lord.
249. If there is a deacon, another assisting priest, or an acolyte present:
a) For the communion of the body of the Lord, everything is done as described in nos. 224 b and c.
b) The communicant goes to the minister of the chalice and stands in front of him. The minister says: The blood of Christ and the communicant responds: Amen. The communicant receives the tube from the minister, places it in the chalice, and drinks a little. The communicant then removes the tube, careful not to spill any drops, and places it in a container of water held by the minister. The communicant sips a little water to purify the tube, then puts it into another container presented by the minister.
250. If there is no deacon, other assisting priest, or acolyte present, the priest celebrant offers the chalice to each communicant in the way described already for communion from the chalice (no. 245). The minister standing next to him holds the container of water for purifying the tube.
4. Rite of Communion under Both Kinds Using a Spoon
251. If a deacon, another assisting priest, or an acolyte is present, he holds the chalice and, saying: The blood of Christ, ministers the blood of the Lord with a spoon to the individual communicants, who hold the plate beneath their chin. He is to take care that the spoon does not touch the lips or tongue of the communicants.
252. If there is no deacon, other assisting priest, or acolyte present, the priest celebrant himself gives them the Lord's blood, after all receiving communion under both kinds have received the Lord's body.