Friends or F-buddies?

Hyunwoo, Yiseul, Nayeon, and Jimin—the four once-inseparable friends coincidentally run into each other in college. The surprise reunion is riddled with confusion, as some members of the group are less than thrilled about the meeting. Everything from their looks to their personalities has changed, and Hyunwoo is soon faced with the ultimate question: "Is it okay to sleep with your friends?!"

(Source: Lezhin Entertainment)