fingering vs jerking off

fingering

noun
  • The act of using the fingers to penetrate and sexually stimulate one's own or another person's vagina or anus. 

  • The act of using one's fingers in the playing of a musical instrument. 

  • A thick woollen yarn for stockings. 

  • A specific method of using the fingers to play an instrument. 

jerking off

noun
  • An act of masturbation. 

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