Himari, ever the devoted sister, visits her younger sister’s household during a trip, scheming to spice up the couple’s relationship. However, upon learning that her brother-in-law is clueless about pleasuring women—even fumbling basic breast play—she panics. “Their marriage is doomed at this rate!”
Driven by sisterly concern, Himari takes it upon herself to “educate” him under the guise of “How-to Sex Lessons.” What begins as awkward coaching soon escalates into clandestine training sessions, her massive melons (Q-cup!) luring him deeper into debauchery. “This is for their sake… right?” she rationalizes, even as her “tutorials” cross every line…