go off vs spit roast

go off

verb
  • To ejaculate. 

  • To explode metaphorically; to become very angry. 

  • To putrefy or become inedible, or to become unusable in any way. 

  • To fire, especially accidentally. 

  • To begin clanging or making noise. 

  • To explode. 

  • To depart; to leave. 

  • To pass off; to take place; to be accomplished. 

  • To like less. 

  • (chiefly UK, of epoxy resins) To cure; to set. 

  • To stop operating; to switch off. 

spit roast

verb
  • To engage in the sexual practice called a spit roast. 

  • To roast meat in this way. 

noun
  • A sexual practice whereby two men service a single sexual partner at the same time, from different ends. 

  • The technique of roasting an animal, such as a pig, over a fire, where the cook sticks a wooden/metal rod through the animal and sets the ends on two sticks to suspend the animal over the fire. 

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