Sounds just like the part of the shirt that is always messed up in the back: collar. When your collar is wrong, you may get full of choler and soon change your color in front of a caller.
choler (n.) IPA Pronunciation: 
anger, rage, wrath
HAMLET
Your wisdom should show itself more richer to signify this to his doctor; for, for me to put him to his purgation would perhaps plunge him into far more choler.
– Hamlet (III.ii)
When your collar is wrong, you may get full of choler and soon change your color in front of a caller.
This word shows up all over the place so it’s a very important word to know when working with Shakespeare. That’s probably because there are a lot of angry people in the plays.
Just my guess.