It's so hard it might burst... Keiko unexpectedly came across her stepson masturbating. Seeing this, she felt guilty. She had noticed that her daughter and daughter-in-law had refrained from sex during her stay. But she had no idea that this was causing her stepson's penis to look so painful... Keiko decided to help out with her hands and mouth. She had intended to at least atone for her sins, but her actions only ignited her stepson's desire.