I see, what about a spell that increases the production of bodily fluids as well? Since a succubus drinks a man a day, would humans be able to develop a potion/spell that say increases the capacity of a man to store or produce semen in amounts that could satisfy a succubus, to maybe satisfy their "one man a day" quota XD Of course all this is meaningless is the succubus will just keep on absorbing relentlessly.
Speaking of which, I remember watching a scene in Dragonball where some bad guys absorb energy and drain their opponents or something. So basically Goku/Vegeta let them absorb so much energy they couldnt handle it and basically popped. So im just curious whether the succubi have a daily limit to how much they can absorb as well, or if they are just infinitey hungry.