ptyalize vs spit roast

ptyalize

verb
  • To spit. 

  • To salivate. 

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 ptyalize and spit roast occurred in a corpus of books? (source: Google Ngram Viewer )