The "Momu" was a ritualistic learning session in which Yrashu tutors would take their young ones into the jungle an teach them the way of Yrashu jungle survival. The session culminated with the creation of a Yrashu mace made from the roots of a hmumfmumf tree, and was said to "take as long as it takes". A Momu presupposed membership of the tribe, so any non-member had to go through a ritual of being adopted as part of the tribe.
Prior to the Battle of Baskarn, a group of Rebels was adopted into a Yrashu tribe and taught jungle survival the Yrashu way. During their Momu, they encountered a hrosma tiger. The acquired skills would prove essential in the defeat of the Empire during the battle.