gratification vs tickling

gratification

noun
  • A feeling of pleasure; satisfaction. 

  • The act of gratifying or pleasing, either the mind, or the appetite or taste. 

  • A gratuity; a reward. 

tickling

noun
  • A sensation that tickles. 

  • The act by which someone is tickled. 

adj
  • That tickles 

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