Reijou Kanritou ~Seifuku Shoujo-tachi no Sakunyuu Reizokuki by Bishop

There is a dormitory at a private school for training high-class ladies, where students are trained secretly 'To Serve Men'.
However, one of the students got pregnant during the training.
To prevent this from becoming a scandal, the pregnant student was expelled and the dormitory was shut down in fear of causing another incident. Many years passed and now the decaying building is awaiting demolition.
The protagonist, the bastard child of the accidental pregnancy, negotiates with the current principal of the school using the story he heard from his mother.
He negotiates to reopen the dormitory, and work there as a manager.
He only has one goal in mind.
To drain the slaves he has raised and taste their milk.
So the dormitory known as the 'Mistress Administration Building' has been revived by the protagonist. The building will be transformed into the 'Slave Management Building; where the sounds of schoolgirls being trained and milked will echo throughout the night.