Somewhere in Tokyo, there is a public toilet called the back toilet, which is used for secret sexual relief. A young girl is brought to a filthy, smelly, closed-off toilet hut without knowing why, and is naked and tied up. She is exhausted and has no energy or stamina to escape. Then, one after another, the men, whose semen is about to leak out, insert their raw penises into her. They release their semen into her vagina, enjoying the feeling of using her tight, narrow pussy. A large amount of real, smelly, thick semen flows back out of her smooth pussy. Then, she spits her stinky, sewer-like phlegm mixed with tar into the toilet, makes her drink her stinky urine, and leaves the toilet feeling refreshed. The roughly handled pussy toilet breaks and she leaks a lot. After serving people and being overworked, this unsanitary human urinal becomes covered in filth and will eventually be disposed of once its role is complete...