Yukina, an office lady who suffers from constipation, finds out about a constipation treatment camp on the internet and takes part in it without much thought. However, it turns out to be an enema-filled anal torture exercise class run by a perverted SM trainer. In order to improve constipation, the muscles around the anus and anal muscles must be strengthened, and the shy woman's anus is forcibly trained! Expansion, foreign object enemas, anal sex, the female trainer's merciless punishment. Relentlessly humiliating and tormenting her anus, the woman has multiple masochistic orgasms from the perverse enema play.