Gustaaf Hulstaert, born in Melsele in 1900, joined the Missionaries of the Sacred Heart in 1917. He received his priestly ordination in 1925 and went to the Apostolic Prefecture of Tshuapa. He was active as a father at the new mission of Boende (1925-1927), at the mission and school annexed to the Huileries du Congo Belge in Boteka (1927-1932) and then at the Petite Séminaire in Boteka (1933-1934). He showed a linguistic interest in vernacular languages and religious teaching. After a leave of absence in Belgium (1934-1936), he became rector of the Bamanya mission, but shortly afterwards he was appointed superior of the mission and inspector of the schools of the Apostolic.

He devoted a large part of his life to the development of a Congo-Belgian linguistic map. See the many articles published in the periodical Aequatoria (1397-1962) published by the Catholic Mission of Coquilhatville. Then he returned to his former position in Boteka (1946-1948). After another leave in Belgium (1949-1951), Hulstaert moved to Bamanya to continue his scientific work and published some reference works on the Lomongo language, ethnographic studies and schoolbooks He was founder of the journal Aequatoria (1937) and a member of the Royal Academy of Overseas Sciences. He was also committed to the rights of indigenous people as a member of the Commission for the Protection of Indigenous Peoples (1953-1960). He received various distinctions as honorary doctors at the University of Mainz and Kinshasa. He died in Bamanya in 1990.

The dance costumes that the initiates wear are that of young men in the days preceding their circumcision. Among them are the kangalas, a group of specialised dancers carrying ritual lances. In the days preceding the opening of a session of gaza wuli, the boys about to be circumcised are called gaza-no (singular: wi-gaza). They dance in the neighbouring villages to announce the imminent start of the ritual. The rhythm to which they dance is called yolo-gaza. Just before the start of the gaza, the young gaza-no decorate the trunk of a Parasol tree in the centre of the village. This ritual pole is called the gambe-te. Before planting it, the bu-gaza, their instructor, pours a protective potion into the hole of the tree and places a small brush there. The rest of the potion is poured into a small pot at the foot of the pole. Before starting the circumcision, the gaza-no plant the gambe-te ritual pole around which many dances will be performed. The novices aim their long zupha whips towards the top of the pole. A small pot containing a potion to ensure abundance during festivities and restore the peace is placed at the foot of the pole. Two days before the opening of the gaza wuli, the young boys each receive two lashes of the whip, after which they will be able to enter the initiation enclosure for the first time. There, they douse themselves in palm oil and red kula/ngula powder and come back outside to dance.

The mothers say goodbye to their sons before they leave for the circumcision ceremony. They are painted in white, the colour of mourning, because their children are going to “die” and then be “reborn” as adults a few months later. Furthermore, if a boy should die during his confinement, his mother will only be told during the ritual’s closing ceremony. When the day of circumcision arrives. The wi-gaza, in this case a kangala dancer, “chief” of the session, leaves his friends and family and gets ready to cross the fence of the ritual area.