Sundome Play de Okashiku Nacchau: Jira Sarete Ika Sarete Irenai Numa

If you put it in, you break up... that's our secret rule.

Orie, a reliable girl with strong self-control, has recently broken up with her cheating fiancé. Disappointed in men, she was talking to a colleague at work about how "if I'm going to date, it should be someone who is honest and doesn't mind not having sex," when her younger, doggy-like junior colleague, Kazuki, sincerely confessed that he didn't mind not having sex, and they started dating. However, when Kazuki asked Orie if it was okay for her to only give pleasure to Orie, Orie realized that in the end, he just wanted to have sex. Confident in her ability to control her sexual desires, Orie decided to tease him by setting the condition, "You can do whatever you want, but if you put it in, we'll break up," but...?

(Source: Akita Shoten, translated)