Bored and idle, Mitsuki and Hikaru were drinking tea in the living room, venting to each other about their boyfriends. When Mitsuki revealed that her boyfriend has a large cock and their sex life is extremely intense, Hikaru felt a twinge of envy. Intrigued by the words "big dick" and "wild sex," Hikaru grows curious about Mitsuki's boyfriend. She proposes an idea—what if they swapped boyfriends? The two girls embark on an exploration of new relationships, drawing intense attention as their encounter unfolds.