Just Friends? (2009)

Cast
Yeon Woo-jin (연우진) as Min-soo (민수)
Lee Je-hoon (이제훈) as Seok-i (석이)
Lee Seon-joo (이선주) as Min-soo's mom (민수 엄마)
Lee Chae-eun (이채은) as Chae-eun (채은)
Moon Seong-kwon (문성권) as Sergeant ( 병장)
Son Cheol-min (손철민) as Visiting center soldier (면회소 군인)

Trailer

Synopsis
Min-soo is on leave from the military and visits his boyfriend Seok-yi. While having fun out on the town, they run into Min-soo mother's mother! When the Min-soo's mother asks about their relationship, Min-soo replies "... just friends." Making things more complicated, Min-soo's mother ends up sleeping between them that night!