Several points of clarification (if we have a Catholic priest or deacon in the thread (or Johnnie Walker), please correct me if I misstated something):
Does the Botafumeiro really swing after mass has ended? My memory may be off, bit I think mass keeps going after the swing. No?
A Catholic priest speaks:
@t2andreo is correct.
The thurible, which is the metal container swung on chains, whihc contains glowing charcoal, on to which (frank)incense is put to make scented smoke, is used liturgically at a High Mass (historically) or at a Mass on a solemnity, (although a priest may choose to use it at
any Mass).
In such a Mass, it is used during the entrance procession, at the beginning of the Mass to incencse the altar, at the Gospel, to incense the book, at the offertory to incense the offerings, and then the celebrant, and then "the people". It is then used at the time of elevation, (part of the consecration), the central part of the liturgy. Thereafter it is usually removed completely and not used again during the Mass.
The last half dozen times when I have seen the
botafumeiro in use in SdC I am quite definite that it was used
after the Mass was finished. Each time I was concelebrating Mass at the altar and on four separate occasions was asked to take part by adding a spoonful of incense to the bowl before it started swinging. I am past getting excited by this but my nephew who had walked with me thought it was uber uber cool!!
My hazy recollection of Pentecost Sunday (a major solemnity) about 8 years ago in SdC was that the botafumeiro was used at the beginning of Mass, but I would not swear to that in a court of law.
The thurible and incense are used also during a funeral Mass, but only after the Mass has finished, during the "final commendation" as a sign of reverence, along with Holy Water, to the body in its coffin.
The thurible and incense are used during Benediction, a devotion where the Eucharistic host is exposed for veneration by the faithful, but without Mass taking place.
It is also used at solemn Vespers (monastic style evening prayer).
Technically then, the
botafumeiro is not used liturgically during the Mass in SdC, (not that I think this is a big issue).
In the "olden days" (just slightly before my time) before the reform of the liturgy following Vatican II in the 1960s there were many rules and regulations, in a book called Fortescue and O'Connell, which listed in considerable detail how and when a thurible should be used, and how many "clicks" different prelates would receive.
A single quote will give you the flavour:
"The double swing ('ductus duplex') is made by raising the thurible to the level of the face, then swinging it out towards the object or person to be incensed, repeating this outward swing, and then lowering the thurible."
You can doubtless infer the existence of a ductus simplex.
Twice recently I was interested to see the use of thurible and incense in a procession at Canterbury Cathedral (Anglican).
Technical note. The metal container which swings and releases smoke is a thurible. The person who carries and swings it is called a thurifer. The incense before use is kept in a container which is called a boat.