Yuri, a plain-looking private tutor, possesses large breasts that are clearly noticeable even through her clothes, constantly tempting her male students. With a weak will, she easily gives in to their demands. When a student who scored 100 on a test says, "You promised you'd let me do it," she lacks the strength to refuse. Her body has become the perfect target for young boys' sperm. This big-titted tutor endlessly offers her irresistible charms to her students.