I’m reading this treatise on Demoniality (sex with demons) written by this doctor in 1879 and goddamn it’s like he custom-wrote it to get every modern monster fucker smitten. He’s explaining all he knows about incubi and how they bind humans to them in exchange for magic powers and what a relationship with them is like.
With a few tweaks you could adapt this into a very popular erotic tale, complete with intricate worldbuilding.











