Seiso na Kanojo wo Nakadashi Chuudoku ni Saseru made

A prim-and-proper girlfriend who has never had any sexual experience with men is about to take her relationship to the next level. After three months of dating, during which they have only ever kissed, her boyfriend gathers his courage and asks her for sex. She feels that their relationship shouldn't remain stuck at that point, and so she gives him her consent.

However, he doesn't wear a condom for her first time having sex. Even as she tries to resist getting creampied, her body quickly turns on her to accept it. This sequence becomes a repeating occurrence, and she finds herself growing addicted to a pleasure she never expected.