My sister's lewd mouth and deep-seated lustful throat are my exclusive oral cavity. (Nagino Tsukasa YST-225)

When her parents were away, Nagano Tsukasa was her younger brother's oral sex slave. Whether in the toilet, the entryway, or the bedroom, her brother's penis was thrust into her mouth until she vomited up stomach acid, and her genitals were also penetrated by her brother…