Bakunyuu Maid Choukyou ~Yakan Kinbaku Kyouiku~

The main character lives in a huge penthouse in a large city that resembles an American city in the 1960s.

He is usually a gentleman, but as soon as the sun goes down, he turns into a lecherous trainer. He is an “educator” who gives SM training to the busty maids night after night.

His treatment is a bit rough, and he rarely expresses his affection for them due to the hard training menu. This is due to his profession as an “exorcist".

These girls who serve the protagonist are in fact "demon possessed".

The exorcist is able to extract demonic energy from the possessed and destroy it. Demonic energy is expelled from the body during a state of sexual arousal induced by pain or pleasure.

The harder and more perverted the SM training, the more efficient it is to bring the possess to a state of sexual arousal. Making the protagonist the exact person these girls need.

The protagonist is on a mission to save his maids with voluptuous tits by subjecting them to SM training.

[From official site]