What ritual surrounded seing the Oracle?

The Oracle was called Agbala, and people came from far and near to consult it....The way into the shrine was a round hole at the side of a hill, just a little bigger than the round opening into a henhouse. Worshippers and those who came to seek knowledge from the god crawled on their belly through the hole and found themselves in a dark, endless space in the presence of Agbala. No one had ever beheld Agbala, except his priestess. But no one who had ever crawled into his awful shrine had come out without the fear of his power. His priestess stood by the sacred fire which she built in the heart of the cave and proclaimed the will of the god. The fire did not burn with a flame. The glowing logs only served to light up vaguely the dark figure of the priestess. (ch.3)