Play by the book informal verb phrase
Sometimes Peter is very boring because he always play by the book.
My team leader always plays by the book and doesn't accept any exception.
To break the rules or refuse to adhere to the regulations.
To find ways of avoiding or breaking the rules, either those of life in general or of a specific structure or organization, in order to achieve your aim
If one commits three mistakes, transgressions, or infractions, he or she will be dismissed or punished very severely.
A rude phrase expressing contempt, disgust, or anger to someone who has a rigid or serious demeanor
The verb "play" should be conjugated according to its tense.
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"Book" in this idiom means a set of rules or moral/ religious precepts. The earliest citation that can be found is from Edgar Allan Poe's Murders in Rue Morgue (1845).
A humorous way of saying that what one has said is just what they acknowledge and may not be entirely accurate
Mike: Have you returned from your vacation on the beach? Your skin seems to get tanned.
Jenny: My skin is always dark. That's my story and I'm sticking to it!