When Yori encountered her stepson masturbating, she offered to help with her mouth and hands. After two weeks of staying at her daughter's family home, she noticed that her daughter and son-in-law were holding back on their nightlife out of consideration for her. If her presence was causing her stepson stress, she wanted to do something to ease it. That was Yori's way of showing concern. However, this action ended up being the trigger for her stepson to develop forbidden feelings.
