STARS-081 The tomboy classmate likes to get laid.

To save her younger brother, who attends a boys' school, from being bullied, her older sister, Mahiro, disguises herself as a man and sneaks into the school, catching the weaknesses of the bullies and being able to stop the bullies. . However, Mahiro is counterattacked by bullies who discover that Mahiro is a woman. At first, Mahiro is very optimistic, but gradually falls into masochistic pleasure, drowning in lust and being disturbed.
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