jock vs whack off

jock

verb
  • To masturbate. 

  • To humiliate. 

  • To steal. 

noun
  • A jockey. 

  • An enthusiastic athlete or sports fan, especially one with few other interests, often stereotyped as slow-witted person of large size and great physical strength. 

  • A Scotsman. 

  • Food; meals. 

  • A disc jockey. 

  • A young male athlete (through college age). 

  • An athletic supporter worn by men to support the genitals especially during sports. 

whack off

verb
  • To masturbate. 

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