“Santapplause” (Santa Claus + applause) is a Christmas portmanteau word. “Broadway Santapplause” was used by New York-born gossip columnist Walter Winchell (1897-1972) in 1946.
 
A riddle has been cited in print since at least 1988:
 
Q: What do you call a man who claps at Christmas?
A: Santapplause.
 
A slightly different riddle was posted on Twitter on December 5, 2009:
   
Q: What do the elves call it when Father Christmas claps his hands at the end of a play?
A: Santapplause!
 
       
19 December 1946, Philadelphia (PA) Inquirer, “In New York” by Walter Winchell, pg. 20, col. 1:
Broadway Santapplause.
   
Google Books
The Schoolkids’ Joke Book
By Brough Girling
Toronto, ON: HarperCollins Canada, Limited
1988    
Pg. 10:
What do you call a man who claps at Christmas?
Santapplause.
 
Google Books
The Father Christmas:
It’s a Blooming Terrible Joke Book
By Raymond Briggs
London, UK: Puffin Books
1994  
Pg. 95:
What do you call a man who claps at Christmas?
Santapplause.
 
23 December 2000, The Mirror, “Driving Us Crackers” by Michael Burke, pg. 31:
WHAT do you call a man who claps when he sees Santa?
SANTAPPLAUSE.
     
8 December 2002, Newsday (Long Island, NY), Kidsday sec., pg. 1:
What do you call a man who claps every Christmas?
Santapplause.
   
Google Groups: alt.humor.puns
Puns of the Weak 12/13/02
Stan Kegel
12/13/02
(...)
What do you call a man who claps at Christmas?
Santapplause ! (Kids Jokes)
   
Google Groups: alt.2600
merry xmas
Sober
12/15/03
(...)
What do you call a man who claps at Christmas ?
Santapplause !
 
Twitter
Bollywood Sargam‏
@bollywoodsargam
Christmas jokes - 2849 Joke: What do you call a man who claps at Christmas
?
Santapplause ! .... http://tinyurl.com/o5lsmz
3:12 AM - 27 Jun 2009
 
Twitter
george ginis‏
@georgeginis
What do the elves call it when Father Christmas claps his hands at the end of a play?
Santapplause!
3:31 PM - 5 Dec 2009
   
Google Books
Christmas Jokes
By Delphon Coker
Xlibris (Xlibrispublishing.co.uk)
2016
Pg. ?:
When Santa does something good and we clap for him, What do we call that?
Ans: Santapplause
 
Twitter
Midlands Arts Centre (MAC)‏
@mac_birmingham
What do the elves call it when Father Christmas claps his hands at the end of a play?
A: Santapplause! #BadJokeFriday
10:45 AM - 1 Dec 2017