Go read this if you haven't yet, (they're "supposedly" messages sent between GD&TOP on CyWorld, a Korean social-networking site back during their trainee days). And I make an allusion to it in the story. If you read them, you'll recognize it. 

Here:
http://www.toptopia.tumblr.com/post/7520298791/between-gd-and-top-cyworld-messages-gtop