beat off vs jerk off

beat off

verb
  • To masturbate, usually a man of himself. 

  • To waste time. 

  • To drive something away with blows or military force. 

jerk off

verb
  • To masturbate, usually a male. 

  • To deceive. 

  • To do nothing; to waste time. 

noun
  • An act of masturbation. 

  • A stunt in which the performer is suddenly pulled off a horse, etc. by means of a cable. 

  • An annoying person. 

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