My sister-in-law Yuu came to Tokyo from her hometown to support my pregnant wife. Thanks to Yuu, my wife has calmed down, but I was banned from masturbating right after she got pregnant, and my sexual desire was at its limit because of Yuu's voluptuousness. The video on my phone was deleted, and with no outlet for my sexual desire, I reached for Yuu's underwear. The next day, Yuu found out about it, but instead of getting angry, when she heard about the ban on masturbation, she made the immoral suggestion, "Shall I help you?"...