Imouto Shokushu Rape ~Fukushuu no Shojo Kantsuu~

One day, the main character suddenly gets tentacles. He is totally confused, but he comes up with an idea.... He has a younger sister. She is so cute, but always cold to him. "I might be able to revenge on her...?" Just when his indecent sexual desire arises, his tentacles start moving against his will, and a tentacle rape starts...