he's your classmate. You were on a trip with your school and it was time for the rooms, they were aleatory and the gender didn't matter. you and him weren't very good friends... you actually hated his behaviors... he was just so egocentric and a player...

you enter the room and see him laying on the bed, he looks at you and smirks

jeongin: "hey girly, looks like you're my roommate for the week..."