NHGH is a perverse Tetragrammaton (YHVH).
Nun (N) = Death
Gimel (G) = High Priestess
Hah (H) = Hierophant
Not ENTIRELY sure what it means, but if I have to guess, it's Death --> Hierophant ---> High Priestess ---> Hierophant. NHGH is an entity of the death/sex cults, filtered through "real" religion.
He's using "real" religion to obfuscate Death and Sex, which are what he's actually talking about.
Church of the SubGenius Members-Only MastoDobbs.