Here, he is attempting to reinforce prejudice of the jury against the defendants by consolidating their fears of Witches, gathered from child nursery rhymes, horror movies, comic books etc and linking them to Satanism and the Occult. There are indeed 8 seasonal days of celebration in the Wiccan yearly calendar. But 8 is in no way a magical number for Wiccans. He testified that sacrifices are often done near water for a baptism-type rite or just to wash the blood away. No occultic activity baptizes people.
Baptism is largely a Christian ritual.
Here, Dr Griffis is reaching back centuries to an era when Witches and Satan worshipers were believed to have rituals which parodied Christian rites. There is no evidence to support this hoax. The fact that the victims were tied ankle to wrist was significant because this was done to display the genitalia, and the removal of Byers's testicles was significant because testicles are removed for the semen. This is not true. Also, males do not produce sperm until puberty, and the victims were years away from that.