OBA-009 Your son is not a virgin. Kumiko Shinzawa.

"Just for the two or three days until the renovation is finished..." Kumiko readily agreed to let Shinji, the eldest son of her neighbors the Uedas, stay over at their house. The next day, Shinji visited the Niizawa residence accompanied by Yuko, his mother-in-law. Junpei, Kumiko's son, couldn't hide his excitement about the life that was about to begin with Shinji... However, Kumiko couldn't forget a certain thing Yuko had said. That is, that Shinji was a "virgin". Intrigued by whether Shinji was really a virgin, Kumiko took bold action after he got out of the bath...