Maybe he means while "Joining your friends session" to go to the "Camo" screen and start rapidly tapping "X,A". The thing is what I understand is you get kicked out of "Lan Party" and back into the "Multiplayer Screen(Where you select Lan, Splitscreen, Multiplayer, etc.)". If this is supposed to happen wouldn't a "Lag Switch" be needed to freeze the "Joining Session" so you would be able to try and change the "Camo" quickly.
Sorry if this sounds really confusing