205. A concelebrated Mass, whatever its form, is arranged in accordance with the norms commonly in force (cf. nos. 112-198), observing or adapting however what is set out below.
Don’t be late!
206. No one is ever to join a concelebration or to be admitted as a concelebrant once the Mass has already begun.
Sacristans, take note:
207. In the sanctuary there should be prepared:
a) seats and texts for the concelebrating Priests;
b) on the credence table: a chalice of sufficient size or else several chalices.
Be prepared to fill in for the deacon, if he’s not there:
208. If a Deacon is not present, the functions proper to him are to be carried out by some of the concelebrants.
First choice for other roles, lay persons:
If other ministers are also absent, their proper parts may be entrusted to other suitable faithful laypeople; otherwise, they are carried out by some of the concelebrants.
Ordinarily, a concelebrant will wear a chasuble. I’ve missed this one, as have many priests I know. Most choose alb and stole:
209. The concelebrants put on in the vesting room, or other suitable place, the sacred vestments they customarily wear when celebrating Mass individually. However, should a just cause arise (e.g., a more considerable number of concelebrants or a lack of vestments), concelebrants other than the principal celebrant may omit the chasuble and simply wear the stole over the alb.
This is all pretty tame stuff. Any comments?