See subjects. When I was a kid, and whined “I’m bored” to my dad, he would say “fuddle your duddle.” I always understood that as “twiddle your thumbs” (ie hold your hands in loose interlocked fingers and rotate one thumb over the other).
A couple of years ago I think someone laughed when I said it, I think because it sounded inappropriate.
It’s also possible my father, an immigrant, heard something that sounded like that, and made it up. I’ve never read or heard anyone use the expression.
Maybe the person who laughed was Canadian?
Are you Canadian? It’s Trudeau.
I’ve never heard “fuddle your duddle”, so I’d hear it as dirty probably is there wasn’t context suggesting otherwise. After all, pretty much anything of the form “He was verbing his noun” can mean what you think it means, with the right inflection or with the right (absence of) context.
I’m not Canadian, but I was 12 in 1971, and my father followed international news closely, and was an immigrant who had mastered English except for new slang, which I suspect he had an ear out for and greedily absorbed. Perhaps he thought it did stand for something dirty–a la Trudeau’s disingenuous expression–and liked it, and said it to me as a kid because he thought it was funny that I didn’t get it.
So Trudeau choose those words just because they sounded funny and the first one begins with an “f?” And has it become a in-joke usage only for people who follow politics of a certain age (hence MikeS and donkeoatey’s response, or has it sort of entered Canadian usage?
For the first, in-joke reference type, I’m thinking similar to nowadays, at least, the words “have a wide stance” cannot be thought of/used in US political writing without thinking of some Senator who was caught trying to find some random homosexual nookie, initially by nudging someone’s foot in the next stall, and who claimed he merely had a wide stance.
Perhaps it will ever remain just one more addition to the list of Canadian inscrutables for this American.
ETA: Pasta on “verbing his noun” is trenchant. And cogent. Unless “trenchant” already implies “cogent.”
So, Leo Bloom, when you were a bored kid, and whined to your father thereof, and he invited you to fuddle your duddle — Did you?
Or did you just sit there and twiddle your thumbs? 
Interesting. I was born in 1966, had Jewish parents from Brooklyn, and my mom said “go fuddle your duddle” too in that exact context, probably early- to mid-1970s as well. Mom had pretty elegant manners and would never have used the phrase if it was knowingly dirty.
(She’d also say “go bang your head against a wall” under the same circumstances. And this was a very loving, gentle woman! I cracked up when Betty Draper used the same phrase in Mad Men. Two more different mothers couldn’t possibly be imagined.)
Some phrases, though unique and original, can be made to sound dirty just by similarity to other phrases and context. Follow almost anything with “, if you know what I mean” and you’ll see what I mean.
A few decades ago, there were some disk jockeys who made a career out of this…“This is Big Bob, the biggest and baddest in the neighborhood, slipping some warm butter into your mornin’ muffin!”, sort of a Howard Stern Lite, until the FCC told them to knock it off.
I had an uncle once who liked the phrase, “Well, I’ll be a dirty bird,” pretty meaningless by itself, but my parents thought that somehow that was inappropriate speech to use to a 8 year old kid. They couldn’t put their finger on it (if you know what I mean), but they felt sure it was scatological and that phrase was prohibited from our family.
That was a catchphrase of George Gobel.
It’s not in usage in the sense that it’s ever used as a replacement for “fuck you” in any generic way, but it’s probably the second most common Trudeau-ism after “Just watch me.” It also doesn’t so much mean “fuck you” as it does “I’m blatantly lying right now by denying that I’ve done the very rude thing which I’ve just obviously done.”
But the beauty of what Trudeau said … and Trudeau, love him or hate him was a very brilliant scholar, lawyer and writer, is he neither confirmed nor denied saying “fuck off”. He was asked what he was thinking when he mouthed something at opposition members. He asked the reporter what is the nature of one’s thoughts when one says “fuddle duddle” or something like that? No fuck was given in the crafting of that sentence, but he made it abundantly clear what he was THINKING.
Nothing like a response six years late. I grew up in Brooklyn, NY during the early 1940’s. Always being a pain in the neck, my mom would frequently remark “Go fuddle your duddle”. I agree with your assessment as to the meaning “twiddle your thumbs” or “bang your head against the wall”. My mom was raised by Jewish/Russian immigrants but I have no idea what the origin of the phrase is. In fact, I was searching for the meaning myself and came upon your post. I’ve never thought of the expression as being “dirty” or “inappropriate”.
the only time I heard the phrase, growing up in Toronto, was the fuss about Trudeau. The papers at the time had trouble with how to describe it - apparently some opposition member had made some comment about Trudeau’s wife (Justin’s mother) and that was his response. he was never terribly patient and easily annoyed by fools.
The papers of the time had difficulty reporting it (IIRC, a little before Nixon’s “[Expletive deleted]” infamy.) One newspaper suggested he said something along the lines of “go forth and multiply”. Which suggests a completely different interpretation of God’s instructions to Adam and Eve.
As for old expressions, one I recall is from the Marx Brothers movies:
Old lady: “Well, I never…!!”
Groucho: “There’s you problem, maybe you should once in a while.”
I told that joke to my niece and nephews back in the 1970’s and my stepsister said “Don’t teach them that! They have great aunts who still say that.”
Miss Fuddle de Duddle was a character in Dr. Seuss’s On Beyond Zebra which came out in 1955. I’d think Geisel would have avoided anything that sounded remotely like such a euphemism in a 1950s children’s book so I’m pretty sure he’d have never heard such. I assume it was something he thought had a playful sound – much like fiddle dee dee.
To clarify my point, “go fuddle your duddle” was an expression my mom used when I was a child during the 1940’s. I’m not familiar with what Mr. Trudeau had said but that would have been decades after my childhood. Both of my older sisters also recall the exact phrase.
I missed Choie’s post of 05-23-2013, we may be related 
OP here. Invite me to to the reunion. My Dad (OP cite) was a Hungarian Jew who came to America in 1945, if this datum helps future lexicographers.
Sounds vaguely masturbatory.
Hi, Leo! I’ve been kinda wondering if your duddle got permanently fuddled, you hadn’t been around in so long.