From T.I. Net:
Around 30, still a virgin. A corporate slave, masochistic. There’s no way anyone could ever like someone like me. Ikeda Ami is an office worker in her thirties. She’s a virgin, socially awkward, and a workaholic. One day, while sitting alone in a park near her home, she is approached by a promiscuous neighborhood boy named Kanata. Ami gets pushed along by Kanata’s casual physical advances and ends up agreeing to play a game where each time she loses, she must obey whatever he says.
As her body is teased and she gradually grows aroused, she realizes that part of her doesn’t actually dislike what’s happening. Their strange relationship continues: training with a collar and mouth gag, outdoor sex on the rooftop of an empty building, and more. But one day, out of nowhere, Kanata himself declares the end of their relationship. Where will this strange master-servant bond between a thirty-something woman and a boy lead? “The real me is the one I know the least.”