The phrase was first used in songs by artists such as The Beatles and shortly after by Simon & Garfunkel. This phrase has absolutley no definitive meaning given by dictionaries or artists such as John Lennon who first used it. The phrase has two other widely known spellings: goo goo g'joob and kukukachu. It is believed to be used in songs and in 60s and 70s slang as a phrase left to be freely interpreted by anyone based on the surrounding context it is used in. The freedom to betsow any meaning upon the phrase makes the word a statement about freedom of expression, which is a meaning in itself.
Another widely accepted variation of the meaning is a slang way to assure the state of things is entirely fine; an expression of reassuring goodness. Also used as a way to introduce an effect or say "hey whatdya know--".
In "That '70s Show", Donna Pinciotti said coo coo ca choo as an end to a random string of rhymes while stoned.
Coo coo ca choo was also used by Crush the turtle in "Finding Nemo".
Man, you been a naughty boy, you let your face grow long.
I am the eggman, they are the eggmen.
I am the walrus, goo goo g'joob.
--The Beatles' "I Am The Walrus"

Hide it in a hiding place where no one ever goes
Put it in your pantry with your cupcakes
It's a little secret, just the Robinsons' affair
Most of all, you've got to hide it from the kids
Coo coo ca choo Mrs Robinson
--Simon & Garfunkel's "Mrs. Robinson"

Little dudes are just eggs, leave 'em
on the beach to hatch, then coo-coo-ca-choo, they find their way back to the big 'ol blue. --Crush from "Finding Nemo"

"Everything is all right." "No worries." "All is good."
by Alyse Toulouse April 21, 2008
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a strictly medical term, used to describe a patient or person that has delved into a realm of irrational, illogical and/or crazy thought processes; Affected with madness; insane to an exceeding degree characterized by weakness or feebleness; decrepit; broken; falling to decay; shaky; unsafe; foolish
See that guy trying to put that square peg into that round hole? I think he's gone coo coo for cocoa puffs!
by message_tied_to_a_brick June 30, 2004
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1. A way to describe someone's behavior when they are being crazy, insane, silly, spontaneous, funny, or wild.
Whenever Alexis and Nate hang out together, they are coo coo banana sandwiches!
by AlexisBrooke November 14, 2011
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coo coo ca choo mean's everything is alright okay and just go with the flow because you got scroll buttons like the day is long.
man how ya feeling? coo coo ca choo good.
by Frank Kong October 11, 2004
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The phrase uttered when a cougar bags her prey.
Me (on the phone with a hot 40ish cougar)
"He's how old?!? Well, Coo coo ca choo, Mrs. Robinson, Coo Coo ca choo."
by groundedsteve September 15, 2011
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