Your neck and its million and one tiny folds only reveal themselves when you are truly relaxed. I like to compare it to that of a tortoise as you like to shrink it back and forth. If you're crying, forget about trying to get in there to clean out the collection of lint and remnants of spit up, making it one of your stinkiest body parts. This means that I am forced to wipe off that "neck cheese" while you're sleeping or nursing. The cold makes you shrink your neck back in, and just like that it disappears again.