masturbate vs shag

masturbate

verb
  • To stimulate someone else sexually without penetration of the penis. 

  • To stimulate or please oneself by means of anything, not necessarily sexual, that does not get them anywhere; something that wastes their time; something that does not help others or achieve any important goal. 

  • To stimulate oneself sexually, especially by use of one’s hand or a sex toy made for this purpose, often to the point of ejaculation or orgasm. 

shag

verb
  • To have sexual intercourse. 

  • To have sexual intercourse with. 

  • To perform the dance called the shag. 

  • To make hairy or shaggy; to roughen. 

  • To shake, wiggle around. 

  • To chase after; especially, to chase after and return (a ball) hit usually out of play. 

  • To masturbate. 

noun
  • A type of rough carpet pile. 

  • A deliberately messy, shaggy hairstyle. 

  • An act of sexual intercourse. 

  • Matted material; rough massed hair, fibres etc. 

  • Coarse shredded tobacco. 

  • Any of several species of sea birds in the family Phalacrocoracidae (cormorant family), especially the common shag or European shag, Phalacrocorax aristotelis, found on European and African coasts. 

  • A fundraising dance in honour of a couple engaged to be married. 

  • A casual sexual partner. 

  • Friend; mate; buddy. 

  • A swing dance. 

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