The rolissisin was a ritual conducted by the Ocampa to prepare their females for conception upon the appearance of the elogium. Normally a parent conducted the ritual, but in unusual circumstances, the female could choose a person with whom they had a close, trusting relationship to act as surrogate.
The ritual was conducted after the appearance of the ipasaphor, which made the mating bond possible. As mating was required begin within approximately fifty hours, performing the rolissisin became a time-sensitive matter.
The person conducting the rolissisin massaged the feet of the female, until the female's tongue began to swell. The massage stimulated the sympathetic nerves in the foot, and set off a hormonal reaction that activated glandular activity in the tissues of the tongue. The ritual took approximately an hour to complete, after which the female joined her chosen mate for reproduction.
In addition to the physiological aspects of the ritual, it also served to help the parent and child move into a new relationship. As a child with her own child, the parent acknowledged the female's true adulthood.
Kes, a two-year old Ocampa female, went through premature elogium in 2371 due to the presence of a swarm of spaceborne aliens. With neither parent available, her choice for surrogate for the rolissisin was Captain Kathryn Janeway. But with Janeway busy dealing with the aliens, Kes enlisted the USS Voyager's Emergency Medical Holographic program. The ritual was completed, but Kes decided not to pursue reproduction at her early age. (VOY: "Elogium")