“Edumacation” is a jucolar spelling of the word “education,” cited in print since at least 1912. A speaker might say “I’se got a good edumacation,” indicating just the opposite of a good education. The “ma” infix is also present in “razzmatazz” and other words.
 
Although “edumacation” was used in the 1910s, the term was repopularized in the 1980s. Other humorous misspellings of “education” include “edjamacation,” “educamation,” “educashun” and “educayshun.”
       
 
Wiktionary: educamation
Noun
educamation (uncountable)
1. (chiefly humorous) Mistaken form of education
   
Urban Dictionary
edumacation
Used to refer to an education that someone received at a crappy school, or a lack of education all together.
I received my edumacation at Willits High School.
by zanny May 26, 2004
 
OCLC WorldCat record
Heinie at college : Mike and Meyer
Author: Joe Weber; Lew Fields
Publisher: [New York] : Columbia, [1912]
Edition/Format:   Audiobook : 78 rpm : English
Summary:
Presents a humorous dialogue in German dialect in which Mike describes to Meyer his ambitions for his son who is in college getting an “edumacation.”
       
7 January 1913, San Antonio (TX) Light:
...come you keeping er post office when you ain’t got edumacation-enough to spell Dusen-...
(NewspaperArchive does not currently make this page available—ed.)
 
Google Books
February 1913, The Violinist, pg. 133:
“See, for de scroll, a man’s headt, mit de orichinal handt carved viskers, vor de pack an inlaid mosaic picture of de city from Paris, undt around de sides carved writing, so old yet de lagvich iss forgot und professors of edumacation from skilledge can’t read it.”
(“Why the Cost of Violins Is Rising” by Thomas V. Purcell—ed.) 
   
Google Books
Schmerecase in School;
A character entertainment for boys in two parts
By George P. Seiler
Boston, MA: Walter H. Baker & Co.
1916
Pg. 23:
HANS. Dot shows der value of higher edumacation.
     
Chronicling America
5 April 1916, Philadelphia (PA) Evening Ledger, Night Extra, pg. 12, col. 1 comic:
MARTIN, I WISH TO PUT YOUR EDUMACATION TO A TEST.
 
Google Books
Raising a Riot:
A comedy in three acts
By Tom Taggart
New York, NY: Samuel French
1952
Pg. 57:
CRACKER. I got me an idee to make a whul heap o’ money — but I got to git me a man with edumacation.
 
Lyric Wiki
Dr. John: Qualified
This song is performed by Dr. John and appears on the album In The Right Place (1973), on the album The Very Best Of Dr. John (1995) and on the album All By Hisself (Live At The Lonestar) (2003).
(...)
Your social life ain’t no better than my hot dog stand
Your edu-ma-cation ain’t no hipper than what you understand
Your woman that you got she ain’t no hipper than a hot loving band
 
Google Books
Natural Lives, Modern Times:
People and places of the Delaware River
By Bruce Stutz
Philadelphia, PA: University of Pennsylvania Press
1998
Pg. 117:
But you could honor and respect the guy who shot a deer, the guy who provided for himself and protected his family and also got his children an “edumacation” as my father called it.
 
Google Books
Berkeley High School Slang Dictionary
By Rick Ayers
Berkeley, CA: North Atlantic Books: Distributed to the book trade by Publishers Group West
2004
Pg. 29:
Edumacation (ED-you-ma-KAY-shun) n., Education. Used in self-deprecating reference to getting an education. When it is said with purposeful mispronunciation, it suggests that the student isn’t learning anything.
(...)
[Origin, ‘80s youth]
 
OCLC WorldCat record
Edumacation 101: Fun with chemistry is no longer encouraged
Edition/Format:   Article : English
Publication: ICIS CHEMICAL BUSINESS- INTERNATIONAL CHEMICAL INFORMATION SERVICES CHEMICAL BUSINESS, 273, no. 19, (May 12, 2008): 50-50
Database: British Library Serials
 
OCLC WorldCat record
The edumacation of Jay Baker
Author: Jay Clark
Publisher: New York : Christy Ottaviano Books, 2012.
Edition/Format:   Book : Fiction : Secondary (senior high) school : English : 1st edView all editions and formats
Summary:
In small-town Ohio, fifteen-year-old Jay Baker’s popular new blog helps him navigate high school as he faces off against his mortal enemy, meets the girl of his dreams, and watches his parents’ relationship implode.