Yukina, a working woman struggling with constipation, joins a constipation treatment retreat she learned about online with a light-hearted attitude. However, it turns out to be an exercise class run by an SM deviant trainer, dedicated to enemas and anal abuse. To improve constipation, one must strengthen the muscles around the anus, the anal sphincter, as the trainer forcefully trains the shy woman's anal opening! Expansion, foreign body enemas, anal sex, and the relentless punishment by the female trainer. Repeatedly humiliated and tormented at the anus, the woman reaches masochistic ecstasy numerous times through perverse enema play.
