Historically, "monkey up" has been used to describe a number of particular actions, from more or less literal (to climb nimbly, as a monkey might) to speculative (to botch something up, as a monkey might if it attempted to perform a serious or difficult task) to obviously fanciful (dress ridiculously, in accordance with a monkey's notion of high style). Here are some historical instances of the various senses of "monkey up," in the specific form "monkeyed up."
'monkey up' as 'climb swiftly and nimbly'
From "Puck's History of Oireland," in [U.S.] Puck (March 12, 1879):
How the ould ancient Oirish got up to the top of the towers to dhraw a sup o' shmoke is not known; but, as was related in a former chapter, Prof. Fitz-McO'Darwin claims that they were undoubtedly the originators of the white race; from their plainly perceptible caudal appendages, it is possible they monkeyed up to the top of the towers for their whiff. (Again regard fig. 2.)
And from Ntemfac Ofege, Hot Water for the Famous Seven (2008):
The boys set the raid in motion. They sneaked into the orchard through some holes in the barbed wire fence and immediately monkeyed it up some well-laden fruit trees.
'monkey up' as 'dress elaborately or ridiculously'
From Samuel Crockett, Little Esson (1907):
"You should see her in pale sea-green, with a tall gold lily in her hand," began Fuzzy Wells, with the unction of reminiscence.
"Your grandmother!" snapped John Glencairn, "d'ye suppose, Fuzzy, that she would come through the streets of Creelport monkeyed up like one of old Hodder's draped models at the Life Class?"
'monkey up' as 'improperly perform, clog, get stuck, or otherwise get damaged'
From Joshua Ramsbotham, "Demolition of Old Masonry and Concrete," in Transactions of the Liverpool Engineering Society, Thirty-fifth Session (November 18, 1908):
The × bit clears better in hard rock, and the chances of rifling the hole and getting "monkeyed up" are reduced, as by the formation of the bit, the possibility of the cutting edge striking twice in the same place is reduced to a minimum. The smith responsible for ...
'monkey up' as 'sneaking or wandering through'
From The Strand, volume 6 (1921) [combined snippets]:
"Seems kinder hard luck, doesn't it?" he said cheerfully. "The fact is, I haven't been back home since the war. I was out in France with the Y.M.C.A., and when we got through I didn't feel I could face these new laws, monkeying up side-streets for your liquor, or taking a drink behind a screen at a Chemist's. Most of my friends were coming across pretty regularly, so I just stayed over on this side."
'monkey up' as 'botch, bungle, or ruin through interference'
From Upholsterers' International Union of North America, Summary of Proceedings Including Report of the Officers to the Convention (1927):
Mr. Chairman, I would rather have you throw that resolution out the window than to monkey it up the way it has been monkeyed up. We want the work in our district. We want the carpet and linoleum mechanics organized and we can never organize them so long as we are going along the lines that we are now, and allowing firms to pay the same payroll to union men in one place and nonunion men in other places.
And from Happy Herd Herald (2002) [snippet view]:
This year I will try to make 3 gallons of the native American [grape] variety known as Delaware. Last year I royally monkeyed it up, and the results were laughable. I tried to be a hero! This year I'm going by the book and making a normal white, the way it's supposed to be done. I love Delaware, when it's done properly it is a serious white, my favorite native, very underrated, and in my opinion can stand upon to any of the fancy varieties.
'monkey up' as 'tangled up or misunderstood'
From Proceedings of the National Fraternal Congress of America (1934) [combined snippets]:
We made this Committee go out and work two years, and now we come up and say, "You haven't brains enough to present anything." We haven't waited to get their explanation. I have heard men talk on this who haven't listened, haven't heard that wonderful report which was given on Monday, and I think they have got this all monkeyed up, because that report would convince a blind, deaf and dumb man, if he were here and heard it, as a business proposition—as a business proposition.
'monkey up' as 'imaginatively concoct'
From Robert Lindsay, Fowl Murder: The Mystery of Between the Lines (1941) [combined snippets]:
"Your guess work is intriguing, and I'll admit that if my affairs were as you suggest, proving George insane would give the opportunity to straighten them out."
"And that's why you monkey up this scheme with Harold."
"One moment. You've contributed a story, which, I claim, is largely fiction. Now I shall contribute some truth."
And from Meredith Willson, Eggs I Have Laid (1955) [combined snippets]:
Fast reaching the phobia stage with respect to being isolated in the parlor for an hour every day with a flute, I monkeyed-up the idea of propping the Youth's Companion on my music stand. Knowing the exercises by heart, my fingers and lips went their chore-ful way while my "mental brain" (to quote Sadie Teed, our hard-girl at the time) was being absorbed in my first amazed excursions into magazine-land.
'monkey up' as 'make needlessly fancy'
From The American Magazine, volume 156 (1953):
He decided, once more, that the best music is the simplest and "least monkeyed-up."
And from National Research Council, Special Report, issues 122–124 (1971):
What worries me more is the question of vehicle design. Do you use a Ford Courier, or a "monkeyed-up" General Motors vehicle, or something else? I am worried that we will go into these things in a hurry and in a fashion that will mar the image and the public response to a demand-responsive jitney.
'monkey up' as 'make a burlesque of'
From The Listener, volume 61 (1959) [combined snippets]:
Didrot's rationalistic pipe-dream about Tahiian man, in a South Pacific Eden, as a natural, noble, simple, and highly sensual machine, remains a remarkably cogent absurdity. Rousseau would have sentimentalized it; Voltaire would have monkeyed it up, but Diderot invested it with a lucid vehemence. The eloquence and paradox of this model dialogue are still very much alive, and the speakers in this programme gave them all their performing value.
'monkey up' as 'have a photographer on hand'
From Sue Margolis, Neurotica: A Novel (2003):
"Anna, angel . . . thought I'd give you a quick bell just to check that you're all monkeyed up for tonight."
It was Campbell in old-style Fleet Street vernacular mood, checking she'd been assigned a photographer—a monkey—for her assignment.
'monkey up' as 'capering about or otherwise behaving like a monkey'
From Daniel Nemiroff, Nasty, Short and Brutal (2006):
"Itsa no use," Gil moans. "Nobody a-wanna see my monkey no more!" Fast forward through Gil pouring his heart out to the crowd, Mickey [Solomon] monkeying it up, jumping into people's laps, kissing women and picking their pockets.
"Ah, but watta can I a-do, my little a-monkey-friend?" Gil finally sighs.
"Talk with a better Italian accent than that," Mickey snaps back through his monkey smile, that knowing primate grin on the backdrop of his fine, slight features that made all the girls swoon.
And from Mick Middles, Breaking Into Heaven: The Rise, Fall & Resurrection of The Stone Roses (2012):
However, the true drama occurred less than a minute into the song, when the Roses' amplification proved too much for the Beeb's power supply, which cut out – all sound abruptly ceased, leaving the band suddenly strumming silent guitars and Ian Brown monkeying it up to no effect at all.
----------------
The unaddressed 'monkey' in the room
Of course, all of these senses of "monkey up" coexist with longstanding scurrilous meanings of monkey, noted in Jonathon Green, Cassell's Ditionary of Slang (2005):
monkey n. 1 {late 16C+} [19C+] a scamp, a rascal, 2 {19C+} a general insult, esp. when used derog. since mid-19C by White people of a Black or Asian person (cf. AFRICAN APE n.; BROWNIE n.). 3 {19C+} a person. 4 {20C+} (Aus./US) (also monkey man) a Chinese person; a Mongolian (cf. AH CABBAGE n.). 5 {1900s–40s} (US Black) a West Indian. 6 {1910s+} (Aus./US) a Japanese person (cf. BUDDHAHEAD n.). 7 {1910s+} a thug, spec. one with no intelligence. 8 {1920s} (US tramp) a member of the public, a non-tramp. 9 {1920s+} (US Und.) a victim of a swindler, a dupe. 10 {1930s–40s} (US Und.) a prohibition agent. 11 {1940s+} (US prison) a correctional officer. 12 {1970s+} (US Black) a White person. {(1) now S[tandard] E[nglish]}
That is to say, since the middle of the 1800s, the term monkey has been used as a racial or ethnic insult by members of various groups of people for members of other groups of people—and the first such widespread explicitly racial usage of the term in English, according to Green, was by white speakers referring to black people. Any use of "monkey" by a white person in discussing the motives or behavior of a black person carries this baggage with it—whether or not the particular instance of usage is innocent of any intention to convey an invidious racial subtext.
---------------
Conclusion
Although I found instances of "monkey [something] up" in the sense of bungle or mess [something] up going back to 1927, the usage is actually somewhat rare. Various other senses of the expression "monkey up" also appear in the historical record, with more or less connection to monkeys and their real or supposed behavior.
In all of the senses noted above, "monkey up" does not necessarily imply racial or ethnic hostility on the part of the speaker toward the person whose behavior is being equated literally or figuratively with that of a monkey. But I think that longtime, unmistakably pejorative use of monkey across racial or ethnic lines casts a shadow over any application of the phrase by a speaker or writer to people of a different race or ethnicity. I wouldn't hesitate to refer to myself as having monkeyed something up, but there are a great many other people in the world whom I would be loath to characterize in that way.
