The Succubus Guild Receptionist

Ald is a rookie adventurer on the rise, but when a quest leads into a succubus nest, his career is in peril. The succubus herself planned to slowly charm him, but after he recognizes her as the adventurer's guild receptionist, she takes a more drastic and direct measure: she places a curse that begins turning him into a succubus.

At first, the change is physical: he just turns into a (well-endowed) woman. But as the curse grows stronger, Ald start acting and thinking like a succubus too: the urge to drain men of their semen keeps getting stronger and stronger...