From Renta!:

Atsushi Kido is an office worker with unusual tastes. Exhausted by days of overwork and power trips from his boss, he stops by his old part-time job, the Discipline Club, and is immediately asked to help out. When he enters the playroom, Atsushi finds a beautiful businessman with the prettiest posterior tied up and waiting...! The man, calling himself Aya, confesses to using his authority to harass people at work, and lifts his hips for a punishment. Atsushi can't get enough of Aya's behavior!