Succubus 48

The key to saving the world turned out to be something completely unexpected.
Abel, the priest of a hero’s party, receives a shocking command one day: “Save the world with your cock and semen.”
Thinking it must be a joke, he is instead confronted by the last surviving member of a supposedly extinct demon race — a succubus named Suzuka. With striking red hair, black horns, and a beauty that surpasses anything in the world, she glares at him with a sharp tongue and an expression that looks ready to devour him.
The only mission given to the two of them is to complete a forbidden ritual known as the “Succubus 48” through their bodies.