Imouto Choukyou Nikki ~Konna Tsundere ga Ore no Imouto na Wakenai!~

The protagonist, a die-hard eroge fan, is into "exposure," "rape," and "training." One day, his real sister, Himeki Ichinose, snapped at him. "Shut up and train me if you're such a nerd!" Though it made no sense at all, this bizarre training life between brother and sister suddenly began. [Translated from dlsite]