I was going with some reviews. Seriously, Sora can get along with anyone _. Anyway, I thought up a few...
Show him this fan fiction website and make him read yaoi things
Replace his key blade with a beyblade
Dye his hair blonde, spike it like Roxy's, and put him in an Organization 13 uniform (lol, then everyone will call him Roxas)
Call him Roxas like, 10 times and watch him go insane
Tell him that Roxas is sorry for taking his key blade (the Kingdom Key) in Twilight Town ;p (Sora's response probably: He took me Key Blade?!)
Tell him that Riku went back into the Darkness (Sora: Great now I have to go to every world again in a sequal. Me: But everyone loves Kingdom Hearts!)
Give him regular sized shoes and tell him "these are much better!"
Tell him that, after he beat Xemnas the fifth time he's still alive...Go find him!
Tell Sora that he's actually the Nobody and Roxas is his Somebody and make them trade places
Tell Sora he has no fans (Sora: I don't? Me: I love you! *glomps*)
*sighs* Well that tired out my brain _ Next is...Demyx :D! I need suggestions because I can only think of things like, "graffiti his sitar" or "call him a wimp" Hope you guys are better at thinking about these kind of things than I am!