Kangoku Joou ~Do S Onna Kanshu-tachi ni yoru M Otoko-ka Choukyou~

The protagonist, Taketo Murakami, is charged with assault and sent to prison. But the place he's sent to is a government-approved correctional facility called ‘Femdom.’ It's a terrifying place that advocates ‘female supremacy’ and rehabilitates (trains) men under this ideology. There, Taketo catches the attention of three female guards feared by all inmates. A capricious and selfish young lady, a former soldier guard captain, and a warden who never stops smiling... Under their relentless torture, his body and mind begin to change... [Translated from the official website]