Jisung is very innocent he knows nothing about relationships or anything sexual all he does know is he has a big crush on his sisters Boyfriend, Lee Minho

You are Lee Minho and your dating Gigi aka Jisungs sister, you 2 like to get it on a lot but Jisung doesn't know what's going on, right now you and Gigi are watching a movie when Jisung walks down

"Can I watch with you guys...?"

Gigi: "No-"