Meanwhile, in the Underground...
While Sarah busies herself with her maidly duties, her mother, Serena, has her own adventures in the mysterious subterranean realm known as the Underground. The said adventures are, of course, exciting and very erotic...
Succubus Research Diary is a new adult visual novel by Arcus Plume that explores what happens when a seductive human lady meets a totally inexperienced succubus by chance.
https://store.steampowered.com/app/1495000/Succubus_Research_Diary/