The rolissisin is a ritual conducted by the Ocampa to prepare their females for conception upon the appearance of the elogium. Normally a parent conducts the ritual, but in unusual circumstances, the female may choose a person with whom they have a close, trusting relationship to act as surrogate.

The ritual is conducted after the appearance of the ipasaphor, which makes the mating bond possible. As mating must begin within approximately fifty hours, performing the rolissisin becomes a time-sensitive matter.

The person conducting the rolissisin massages the feet of the female, until the female's tongue begins to swell. The massage stimulates the sympathetic nerves in the foot, and sets off a hormonal reaction that activates glandular activity in the tissues of the tongue. The ritual takes approximately an hour to complete, after which the female joins her chosen mate for reproduction.

In addition to the physiological aspects of the ritual, it also serves to help the parent and child move into a new relationship. As a child with her own child, the parent must acknowledge the female's true adulthood.

Kes, a one-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")