There are four participants in this Rite of Communion with Cthulhu, The High Priest of the Great Old Ones. These are: the host of Cthulhu, the Priest or Priestess, and the two worshippers.
The Temple of Cthulhu is to be sparsely lit, and incense of Neptune is burned to infuse the air with an undersea atmosphere (evoking sunken R'lyeh). No images or icons of the God should be present within the Temple, for manifestation is to take place only through the Host. No amulets or decorated robes are to be worn.
The following magickal weapons are utilised:
The Dagger, to trace the Elder Sign; the Chalice, to recieve the Communion from the Host of Cthulhu, and to convey it to the Celebrants of the Rite (prior to the commencement of the ritual, the chalice is filled with salt water, the medium of transmission of the Communion, also symbolising Great Cthulhu's watery grave); two ritual drums are also employed, one by each worshipper.
The symmetrical Trapezoid of Invocation is drawn out in white or blue chalk, its shortest edge to the West (R'lyeh). The Celebrant who is to manifest the Host sits within the Trapezoid at this side, facing inward. The Priest or Priestess sits within the Eastern side, facing the Host. The Worshippers take their positions to the North and South, within the points of the Trapezoid. Once silence has fallen the rite is begun.
Standing, the Priest or Priestess of Cthulhu performs the primary banishment by tracing the Elder Sign (upright pentagram) towards the four cardinal points, beginning to the West and proceeding in an anti- clockwise rotation (the tracing of the Elder Sign begins upwards from the bottom left-hand point). The following God-names of the Great Old Ones are pronounced with the completion of each pentagram: to the West, CTHULHU; to the South, YOG-SOTHOTH; to the East, HASTUR; and to the North, SHUB-NIGGURATH.
The Priest or Priestess now resumes the seated position before the Host, and makes the Call to Cthulhu:
"Ph'nglui mglw'nafh Cthulhu R'lyeh wgah'nagl fhtan"
(In his house at R'lyeh dead Cthulhu lies dreaming.)
The Host and the Worshippers answer this call:
"Ia! Ia! Cthulhu fhtagn"
(Yes! Yes! Cthulhu dreams!)
The Priest or Priestess now begins to chant the Call to Cthulhu in its shortened form, as a Mantra of Invocation:
"Cthulhu R'lyeh fhtagn"
(Cthulhu dreams in R'lyeh)
The two worshippers join with this Mantra, using their drums to counter- point the chanting, thus forming a net of rhthymic sound to draw the Presence of the Deity into the Trapezoid. The Host, however, is silent, for he or she is to remain open to possession by the invoked God-force. In order to encourage this possession, the Host should concentrate all mental and physic energy into a visualisation of the image of Cthulhu, and attempt to identify this image with their own body and mind. The physical position to be adopted by the Host should therefore be that traditionally associated with Cthulhu - that is, crouching or sitting, legs apart, with hands resting on knees. The other celebrants should likewise project their own visualisations of Cthulhu onto the figure of the Host.
Once the presence of the Deity is felt within the Trapezoid (this may be noted by a marked drop in temperature), the Priest/Priestess will begin to direct its energies towards the Host, via magickal passes performed with the left hand. This is to be undertaken in sympathy with the rythyms of the Mantra - a powerful focal point is thus induced within the body of the Host, forming both a strong attraction to the God-force invoked within the Trapezoid, and a physical gateway for its manifestation.
At the moment of possession, the power and identity of the Great God Cthulhu will be drawn into the body of the Host. At the last instance before total possession, the Host calls forth the name of the God, and the Temple falls silent. His power is radiated forth by the Priest/ Priestess, who holds out the Chalice to collect these negatively-charged emanations (Dreams from R'lyeh).
When the Dreams of Cthulhu have passed from the Host (often leaving them mentally and physically exhausted), the Priest/Priestess offers the collected emanations for consumption (via the medium of the salt water), firstly to the Host, then to the two Worshippers, and lastly partakes of the Communion him/herself.
Following the giving of Communion, the Priest/Priestess repeats the Banishment, retracting the Elder Sign at the cardinal points, and repeating the respective God-names. Facing the West once more, he/she declares the Rite of Communion of Cthulhu completed, and the Temple closed. The participants may now leave the Trapezoid, infused with the trans-Yuggothian energies of the Great God Cthulhu.