“If you sprinkle when you tinkle, be a sweetie and wipe the seatie”

“If you sprinkle when you tinkle, be a sweetie and wipe the seatie” (or “If you sprinkle when you tinkle, please be neat and wipe the seat”) is a popular sign displayed in many bathrooms. “If you sprinkle when you tinkle, please be neat and wipe the seat” was cited in 1976 as a library bathroom wall graffito. “If you sprinkle when you tinkle, be a sweetie and wipe the seatie” was cited in a 1978 newspaper advertisement for a toilet seat cover.
 
     
Google Books
Journal of American Folklore
1976
Pg. 43:
If you sprinkle
When you tinkle.
Please be neat
And wipe the seat.
 
Google News Archive
9 October 1976, The Gazette (Montreal, Quebec), “American graffiti: Now they’re analyzing the writing on the washroom walls” by Harry Bruce, The Canadian magazine, pg. 2 (?), col. 3:
Three American social scientists recently published an impressively stuffy paper entitled Anonymous Expression: A Structural View of Graffiti, and in it they solemnly explain that, among the toilet-wall scribblings they’d decided were simply “beyond the scope of the present analysis” were such “traditional” masterpieces as the one that begins, “If you sprinkle when you tinkle…”
     
10 December 1976, Hutchinson (KS) News, “Good news for janitors: Graffiti drops off at HHS,” pg. 16, col. 3:
Some of it is really funny—like the one in a library bathroom that reads ‘If you sprinkle when you tinkle, please be neat and wipe the seat.’
 
31 May 1978, Wisconsin State Journal, sec. 1, pg. 14, col. 4 ad,
IF YOU SPRINKLE WHEN YOU TINKLE BE A SWEETIE AND WIPE THE SEATIE
(A toilet seat cover sold at Creative Classics.—ed.)
 
Google Books
Still More of the World’s Best Dirty Jokes
By Mr. “J.”
Secaucus, NJ: Citadel Press
1981
Pg. 19:
If you sprinkle when you tinkle . . . be a sweetie and wipe the seatie.
     
Google Books
Alma:
A Novel
By Gordon Burn
Boston, MA: Houghton Mifflin
1992  
Pg. 99:
‘If you sprinkle when you tinkle,’ a rather startling little notice in there says, ‘please be sweet and wipe the seat.’
 
Google Books
The Everything Etiquette Book:
A Modern-Day Guide to Good Manners
By Leah Ingram
Avon, MA: Adams Media
2005
Pg. 260:
It would be wonderful if everyone respected that cute little poem that you’re bound to see in a restroom at some point in your life: “If you sprinkle when you tinkle, please be neat and wipe the seat.”
 
Google Books
Grin and Bear It:
How to Be Happy No Matter What Reality Throws Your Way
By Jenni Pulos and Laura Morton
New York, NY: St. Martin’s Press
2014
Pg. 124:
As a reward for my respectful bathroom behavior, I am trusted by Jeff to tell employees and contractors the following: “If you sprinkle when you tinkle, be a sweetie and wipe the seatie.”