In Norfolk, when a child misbehaves in a demanding, or sulking way, they are often said to 'put on their parts'.
'She is putting on her parts again', means that she is following a pattern, typical for her, where she is being loud, difficult, insistent or awkward.
It can also be used for adults and has an added force since it suggests they are behaving like a child. But I am wondering if the expression is widely understood?
Presumably it derives from the following meaning of the noun 'parts':
Meaning 12 of on-line OED
†a. A character sustained, assumed, or feigned by a person, esp. for a special purpose. Also in extended use. Obs.
earlier references deleted.
a1732 J. Gay Fables (1738) II. vi. 47 The man of pure and simple heart Through life disdains a double part. 1885 Dict. National Biogr. at Thomas Blood, It is not improbable that he was at this time..acting a double part, keeping the government informed of so much as might secure his own safety.
Best Answer
Per comments to the question, I personally am not familiar with this (apparently, highly localised) dialectal usage. But my guess is parts here is being used in much the same way as ...
Picking up on the theatrical allusions of "parts", one could also see it as another way of saying...
Given the low prevalence of an expression which seems to be almost exclusively spoken, colloquial, I think it's unlikely anyone will be able to turn up a "first use" from which one might be able to determine precisely what was in the minds of the people who originally used the term.