Yuko Ishihara, a teacher at a school, has decided to live as a sex slave for a certain man. As a symbol of this, she has been fitted with a nose ring like a livestock cow. She hides this nose ring under a mask and teaches her students. While her nostrils were small at first, they have now been stretched to the point where she can hang a padlock on them. Yuko's physical modifications aren't limited to her nose ring. She also has piercings, and a steel dildo weighing close to a kilogram is hung from one of them to train her labia to stretch. Her nipples have also been modified to enlarge and elongate, now as big as a baby's penis. Her anus is still under development, but she's already able to take it, and she's expected to undergo further expansion training with thicker objects. Usually, a padlock serves as her chastity belt, attached to her piercing, and the key is kept by her master. The video consists of footage of her daily training sessions and group play with guests. As a special bonus, there's a slideshow of photos taken together. [Before purchasing] This work is a play submission video shot by amateur SM enthusiasts themselves. There are no AV-like acting, directing, or storylines. It's a raw and erotic visual record.