GVG-670 I'm Secretly Giving Sex Education to My Brother-in-Law... Kanon Kimiiro

Kanon, a female teacher, lives with her husband and his younger brother. Coincidentally, she also serves as the assistant homeroom teacher for her brother-in-law's class. One day, her brother-in-law asks her to "learn about the female body." Kanon is confused, but in order to fulfill his wish, she uses her own body as both an older sister and a teacher to teach him sex. However, before she knows it, that sex education turns into incestuous sex...