Abandon: 100 Nuki Shinai to Derarenai Fushigi na Kyoushitsu Episode 1

Students find themselves trapped in the enclosed space of their school with a mysterious creature called “Ruler” and forced into a dark sex game by the will of mysterious forces. There is a battle royale element to the story, in which players use their “game powers” to force each other to cum, for example, transforming into a demon, releasing depraved tentacles or applying Futanari torture.