Ryuu Yamato

Kazuya Niimi, a student at a music university, is known for having "immobile fingers"—hardly fitting for someone aspiring to be a pianist. One day, due to a sudden twist of fate, Kazuya finds himself lost in another world. In this strange new world, men are not treated as people—it is a society of overwhelming female supremacy and male subjugation. But in that world, Kazuya notices something strange happening to his body. His fingers now hold a mysterious power. Fingers that cause anyone they touch to physically react.

One day Takumi, a university student who writes erotic novels on the side, is approached by his beautiful classmate Otoha Nodoka. She says that she's a fan of his work, then suddenly shows him a video of herself masturbating and asks him to help her become successful as an amateur porn star

A man time-leaps back to the 90s to save his love from a tragic death. But despite his best attempt he can't change her fate until he learns that the only way is to cheat on her with other girls.