My sex slave is a classmate

The Kirishima family holds the long standing tradition that the head of the company must train and maintain a sex slave as an obedient partner. Young Masato must find and train a female slave to take over his father's position as CEO of the group. Masato's father has left his slave (secretary) to help young Masato to find a suitable candidate. Masato turns to his classmates in hopes of finding a suitable female sex slave. Three girls rise to the occasion. He must put those girls through intense training so he can choose the best one. Your choices help Masato to find the best female sex slave.