Youngest sister In Law 2 (2019)

Hwa-jeong and Geon-woo are getting married soon. Geon-woo introduces his friends, Jae-kyeong and Yi-soo, to Hwa-jeong. After a few drinks, everyone goes to Yi-soo's house for a second round. The party ends late at night and Jae-kyeong, who is a lightweight, staggers to the bathroom. He then mixes up the rooms and falls asleep in the room Hwa-jeong is sleeping in. By accident, Jae-kyeong ends up sleeping with his friend's bride.