Open Up!

Mun Yeon-Su, a returning college student, gets blindingly drunk and accidentally stumbles into the wrong apartment - one that happens to share his same door code. Inside, he witnesses a shocking, intimate encounter between his department T.A., Yun Do-Ah, and his classmate, Hong Yi-Jae. Though he tries to process his mistake the next morning, Yeon-Su find himself unable to forget the intense pleasure he caught a glimpse of. When he runs into the duo again, his chaotic and spicy campus life truly begins.

(Source: Lezhin US)