Ga-yung pounces on Kyung-Ho at the bar's bathroom but they get interrupted. Once they're out of there, she invites him for a fancy jacuzzi hotel room where they obviously bang to their hearts content.
After getting pretty drunk, Seung-Ah (FMC) makes a bet with her drinking buddie Kyung-Ho to see if she can get him hard by blowing his dick. fair to say, she won that bet pretty easily. After getting hard he pounces on her, but he fumbled at the last moment by namedropping his ex-girlfriend.
Nam-Wook takes Ga-yung with him to an empty classroom (it's not empty) and fucks her really close to the locker where the Kyung-Ho & Seung-Ah were hiding.
After nude modeling for Professor Cha, Kyung-Ho and Bora dine together. They later go to her place and after chit-chatting for a while, they get horny and have sex.
Seung-Ah lists the good things about Kyung-Ho ...it's only his big dick. Instead of feeling bad he gets horny and talks his way into having sex with her again.