This rustles my jimmies
seems like a commonly used idiom recently to denote being annoyed, angered, touched. Still, every idiom has some origin, and I wonder what is the original meaning of this one.
Similar to the idiom getting your panties in a bunch, I will hazard a guess that jimmies is a complementary masculine phrase. Jimmies may have originally referred to the male member (or accompanying anatomy). At least one instance occurs in the December 2003 issue of Men's Health.
In the article, "in their grip" refers to wearing a condom.
As for rustle, this definition seems likely:
This is just one example of getting your X in a Y or getting your (noun) (verbed) (e.g. getting your titties in a twist, getting your biscuits flipped, and so on). The gist of these expressions is that one is annoyed, angered, or upset. The severity or crudeness of the language may describe the intensity of emotion felt by the "rustled".
Jimmies works as a malleable, polysemic construction. Since it can mean nearly anything, the phrase can be employed in multiple situations, increasing its popularity.
We may never know what the jimmies being rustled are. But here's a summary of the 24 Urban Dictionary definitions for jimmies, oldest first (the page number is the page the definition appears on, highest votes are on the first page):
To summarise, only one refers to something being rustled, and this is the latest but highest voted, and came after the June 16th, 2010 date that Know Your Meme identified for the gorilla image macro so doesn't tell us anything.
There's two definitions for pyjamas, two for male genitalia, one for condoms, and four other miscellaneous entries.
However, the earliest and most frequent definitions (12 in total, and one derived definition) are for chocolate (or rainbow) rod-shaped sprinkles you put on yoghurt or ice-cream, a slang term of the north-east US, particularly Pittsburgh, South Jersey, Boston and New England.
Rustle my jimmies may be referring to the sound chocolate sprinkles make in their box. If so, the Sep 18, 2008 definition provides an etymology of the name jimmies:
A 2009 Snopes article delves into the pre-rustle etymology of jimmies and suggests the Just Born story may at least partly true.
I wondered this myself & after some searching on Google, I came across this site that seemed to be the most authoritative & comprehensive source of information available: