The sacrifice of the sacred bull/calf deep in the underground cave, underlines the dualistic nature of the Mitraic Cult. The sacred bull was in its true nature a fetishist manifestation - phallus, of a multitude-form creator solar deity, a symbol of the sky and heavens, which through this ritual sacrifice ejaculates its seeds (blood) of life. While the underground cave , where Mitra was born from a stone, symbolized the interior (uterus) of the mother earth, which is about to be fertilized by the blood/seed of the celestial bull deep inside her. The death was the symbolic rebirth in the same time, as the sexual culmination is often compared with the “small death.”
This symbolic sexual “penetration” of the celestial bull/phallus deep into the underground womb of the mother earth, can be deduced also from the unmistakably Phallus-like shape of the Mitraeums, the cave-like shrines of Mitra, where at the end of each the altar represented the ‘glans’ of these penis-shaped structures, and