Hyouhen Eros - Watashi o Nurasu no wa Dare?

"He was so nice a second ago, but now he's doing this!? He changed so suddenly, and his you-know-what is so great that I can't stop cumming..." That was a few hours ago. Tomboy Tamaki disguises herself as her bullied twin brother Hisaki and goes to his school for revenge. She immediately gets into a fight with some punks, when she's rescued by Kanan, Hisaki's friend. He seems strong, gentle and an all-around good guy at first, but something causes him to suddenly change! He's a completely different person!! Facing such a sadistic personality, will Tamaki...!?.