A priest of Calistria capable of casting augury, divination or commune is capable of casting the spell as part of an hour long ritual involving profound physical intimacy with a second party, who becomes the recipient of whatever information is gleaned from the divinatory magic. (Adepts in service to Calistria add augury and divination to their spell list, but can only cast them in this manner.) It is rumored that the priest is also aware of the information gleaned, but bound by the sacred nature of the connection to not share that information. The official stance is that only the 'client' receives the information, however. The act itself typically takes about a half hour, with the information being received during a thirty minute period of slumber on the part of the client, which tends to support the interpretation that the priest does not receive the revelation, as the priest does not fall asleep once the physical component of the ritual is complete (and does not even have to remain present, being able to leave and engage in other activities without disrupting whatever revelations become known to the client over the next half hour, during which the client remains in a deep slumber, as if under the influence of a sleep spell).
Despite the name, and salacious assumptions, the act of intimacy does not need
to involve actual intercourse. The client must be brought to the point of release
by the priest, by whatever level of contact the priest feels comfortable, at
which point the client falls asleep and receives whatever divinatory revelations
are available, based on the abilities of the priest in question. In the exceedingly
rare event of a child being conceived as the result of copulomantic divination,
the child is said to have been touched by Calistria herself (not entirely blessed,
not exactly cursed), and to be a harbinger of strange portents and uncertain
times. Such a child may well find herself a child of destiny, with the Sorcerous
potential to match that Destiny.