“Piña colonic” (piña colada + colonic) is a jocular drink name. “Piña colonic,” a mistake for “piña colada,” was mentioned in the Cheech & Chong comedy film Nice Dreams (1981). American comedian and actor Robin Williams joked about “piña colonics” in 1984. Homer Simpson, on the American animated sitcom The Simpsons that aired on January 31, 1999, sang about “piña colonics” to the tune of “Escape (The Piña Colada Song).”
 
A riddle was posted on Reddit—3amjokes on February 21, 2018:
 
Q: What frozen alcoholic beverage should you drink if you need to poop?
A: A Piña Colonic.
   
     
Wikipedia: Piña colada
The piña colada (/ˌpiːnjə koʊˈlɑːdə, -nə-, -kə-/; Spanish: piña [ˈpiɲa], “pineapple,” and colada [koˈlaða], “strained”) is a sweet cocktail made with rum, coconut cream or coconut milk, and pineapple juice, usually served either blended or shaken with ice. It may be garnished with either a pineapple wedge, maraschino cherry, or both. The piña colada has been the national drink of Puerto Rico since 1978.
             
Wikipedia: Colon cleansing
Colon cleansing (also known as colon therapy) encompasses a number of alternative medical therapies claimed to remove nonspecific toxins from the colon and intestinal tract by removing any accumulations of feces. Colon cleansing may be branded colon hydrotherapy, a colonic or colonic irrigation. During the 2000s internet marketing and infomercials of oral supplements supposedly for colon cleansing increased.
       
15 June 1981, The Arizona Daily Star (Tucson, AZ), “‘Nice Dreams’ another ‘reefer-madness’ spinoff” by Jacqi Tully, pg. C3, col. 4:
Sit on a beach and drink “piña colonics,” for one.
 
16 April 1984, The Daily Dispatch (Moline, IL), “Robin Williams an ‘original’” by Michael Blowen (Knight News Wire), pg. 20, col. 1:
DURING a recent 90-minute interview at the executive offices of Columbia Pictures, Williams would impersonate a drag queen, mimic the late George Jessel as Polonius, create a Marin County, Calif., housewife going for “Pina colonics” and toss in a dozen accents for good measure.
 
Los Angeles (CA) Times
Movie Marketplace
Entertainment: Buyers from all over the world flock to American Film Market for nine days of nonstop screenings and deals.
March 06, 1996 | JAMES RAINEY | TIMES STAFF WRITER
(...)
Seeking to distinguish himself in this genre is Dr. Ron Schwartz, an Atlanta gynecologist who spent $20,000 this week to fly three cohorts to Los Angeles and rent a room at the Loews to promote “Smooth Operator.” This personally produced sex farce is big on busty nurses, bathroom humor (a patient will be given a “pina colonic”) and broad racial stereotypes.
   
Google Groups: rec.arts.tv.mst3k.misc
MSTogenous zones
Bill Livingston
2/5/97
(...)
What about a Pina Colonic?   
 
Wikisimpsons
Lyrics
Do yo like piña colonics
And getting caught in the rain…
Passing out in the ocean…
Behind the Laughter
The song is a parody of “Escape (The Piña Colada Song)”.
Appearances
The Saga of Carl - title screen.png Episode – “Sunday, Cruddy Sunday”
Wikipedia: Sunday, Cruddy Sunday
“Sunday, Cruddy Sunday” is the twelfth episode of The Simpsons’ tenth season. It first aired on the Fox network in the United States on January 31, 1999, just after Super Bowl XXXIII and the premiere of Family Guy.
 
Google Groups: alt.tv.simpsons 
Pina Colonic
Ms. K
2/3/99
Not *colitis*.  Homer got a coupon for a free *colonic* - which is an enema. (And if you don’t know what that is, I’m not about to go into it.) The joke was that he was singing “The Pina Colada Song”, as in the coconut drink…and….well, you get the rest of it.
   
24 January 2000, Medical Economics, “‘Go to Mexico,/ I told my patient. ‘I’ll go with you’” by Linda M. Case, pp. 91-92, 95:
“Good, good, although that . . . What was that drink last night? A pina colonic? It sure was rich.”
 
“Pina colada, Andy,” I laughed.
 
Google Books
The Collected Plays of Neil Simon
By Neil Simon
New York, NY: Simon & Schuster
2005
Pg. 291:
CAROL. Max looks terrible. What’s he been drinking, Kenny?
KENNY. Pina colonics, I don’t know . . . The man just ate a roast beef sandwich the size of a Buick.
(From the 1993 play, Laughter on the 23rd Floor.—ed.)
 
20 March 2005, Chicago (IL) Tribune, “No. 126: Readers are mixing it up,” pg. 6:
Pina Colonic: Pineapple juice, rum, laxative. Serve from a hose.
Dave Zuda, Worth
     
Twitter     
Tamar Wallace‏
@justTamar
Replying to @Grafixgibbs
@Grafixgibbs LMAO! Yup. That sounds like Homer. Yummo. A Pina colonic.
11:07 AM - 16 Jun 2008
   
YouTube
Cheech & Chong’s Nice Dreams - Trailer
YouTube Movies
Published on Dec 22, 2013
1;00
“Sipping Piña Colonics.”
   
Urban Dictionary
Pina Colonic
A term used by Homer Simpson during the episode ‘Sunday, Cruddy, Sunday’. It’s an obvious reference to the 1979 song ‘Escape’ by Rupert Holmes (also known as the pina colada song)
‘If you like pina colonics and getting caught in the rain, passing out in the ocean.’
#the simpsons#pina colonic#parody#escape#1979#rupert holmes
by OzramNeje March 11, 2015
 
Twitter
Jay Sharp‏
@jayberino
I invented a new beverage just in time for the weekend.  A cleanse and a cocktail all in one.  It’s the new piña colonic!  #wellness
12:42 PM - 16 Jun 2017
 
Twitter   
kyle‏
@kylefalling
When you drink too much coconut rum that it gives you the shits the next day.
Piña colonic.
11:26 PM - 14 Oct 2017
 
Twitter
Jym Dingler‏
@JymDingler
The Piña Colonic Song #MiddleAgeASong
4:46 AM - 21 Nov 2017
 
Twitter
Art O’Donnell‏
@Art0Donnell
Laxatives and pineapple Jell-O: a piña colonic.
Also, my dinner tonight. #colonoscopy
4:42 PM - 11 Jan 2018
 
Reddit—3amjokes
What frozen alcoholic beverage should you drink if you need to poop? self.3amjokes
Submitted February 21, 2018 by HardlyNetworking
A Piña Colonic