Yeonae Yehaengyeonseup

Returning university student Yun Se-Jun meets a man who looks like Seong-Jae, his childhood crush, but is disappointed to find out it's not him. Later at a drinking party, Se-Jun overhears that the man is actually school idol Jin Do-Won, who has excellent grades, appearance, and personality. Do-won takes the now-inebriated Se-Jun to his house and sleeps with him. The next day he makes a suspicious proposal to Se-Jun. Let's have a love rehearsal!

Se-Jun is shocked, thinking Do-Won is a madman, and is on his way out of the house, when he accidentally steps on an expensive watch that fell on the floor and breaks it...?!

(Source: BOMTOON, translated)