get it on vs shag

get it on

verb
  • To have sex. 

  • To engage in a fight. 

  • To hurry up; to get a move on. 

  • Used other than figuratively or idiomatically: see get, it, on. 

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 get it on and shag occurred in a corpus of books? (source: Google Ngram Viewer )