jill vs knock one out

jill

verb
  • To masturbate. 

noun
  • Coordinate term: (sex) hob 

  • A pelvic protector, a woman’s equivalent of a man’s jock. 

  • A female ferret. 

knock one out

verb
  • To masturbate. 

How often have the words jill and knock one out occurred in a corpus of books? (source: Google Ngram Viewer )