Hentai "Cornelica, City of Succubi" is based on the game of the same name by studio Dieselmine, released in 2017. 

The main character of the story drank too much at a local bar and passed out. He woke up from a strange glow, holding a strange stone in his hands, and sexy succubi were roaming everywhere. He ended up in the land of succubi! To get back, he must give enough magical energy (sperm) to the succubi. Will he be able to return or will he remain a sex slave for the rest of his life?