Chichigami-ke no Yakata ~In'yoku no 247~

Overworked at a black company, the protagonist suffers from erectile dysfunction that even his favorite prostitute can't cure. She mentions a hidden hot spring deep in the mountains, said to restore sexual desire. Determined to find it, he sets out, but a sudden change in weather leaves him in danger. By chance, he stumbles upon a Western-style manor. Welcomed by the maid, he is given shelter by the Chichigami family. That night, Manami, wife of the head of the household, approaches him: 'For one week, I want you to be my two daughters' night tutor and teach them how to attend to someone at night.'