backscratcher vs backslapper

backscratcher

noun
  • A long slender rod with a rake-like device on one end, sometimes in the form of a human hand, designed to let a person scratch their own back. 

backslapper

noun
  • One who makes a show of liking another person with profuse or excessive displays of camaraderie, such as vigorous hand clasping, back-slapping, hearty words of greeting, etc. 

How often have the words backscratcher and backslapper occurred in a corpus of books? (source: Google Ngram Viewer )