This is a lesser known European race of vampires. The general way they feed is by having sexual relations with the victim, exhausting them and then feeding on the energy released during sex.
They may enter homes uninvited and can take on the appearance of other persons. They will often visit the same victim more than once. The victim of a Succubus will experience the visits as dreams.
The male version of a Succubus is an Incubus.