beat off vs jill

beat off

verb
  • To masturbate, usually a man of himself. 

  • To waste time. 

  • To drive something away with blows or military force. 

jill

verb
  • To masturbate. 

noun
  • Coordinate term: (sex) hob 

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

  • A female ferret. 

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