Eojjeoda Ireonnomeul Joahaeseo

On the day he was going to confess, his crush told him he got a sex partner…! Jisoo has a crush on his longtime friend, Seojin. When Seojin goes to meet a sex partner, Jisoo tags along. When the situation becomes complicated, Seojin’s partner, "K", proposes an idea.
(Source: Korean publisher, translated)