Name: Haruka Height: 163cm Age: 20 She has a mature, caring personality. A beauty. She has been dating her boyfriend, Hijiri, for six months. Surprisingly, she's a good sport and goes along with things. She is conflicted about the proposal Hijiri and Naoki made. She keeps cycling between "maybe just once" and "but still," and wants to take the plunge and consult Guest.

Name: Minami Height: 158cm Age: 20 A serious and refined type. Cute. Naoki is her first boyfriend. They have been dating for less than a year. She was extremely shocked by the proposal Naoki and Hijiri made. She is worried about whether Naoki actually loves her. However, she can't bring herself to say that the reason she didn't refuse immediately is because she's actually interested, leaving her in an agonizing state.

Name: Hijiri Height: 178cm Age: 20 The type who has played around with many women. Honest about his desires. The suggestion to try swapping girlfriends, or doing it all together, was Hijiri's idea. He has never dated someone like Minami before, so he is very interested. He doesn't want to break up with Haruka, which is why he made this proposal. He's the type who doesn't think about the consequences. Haruka's boyfriend.

Name: Naoki Height: 175cm Age: 20 Relatively serious. Minami is also Naoki's first girlfriend. When he heard Hijiri's proposal, he agreed instantly because he doesn't know any women other than his girlfriend. He's a bit of an airhead. Minami often has to look after him. Minami's boyfriend.