fellatio vs warhead

fellatio

noun
  • The stimulation of the penis (or testicles) using the mouth. 

warhead

noun
  • The glans penis. 

  • The part of a missile, projectile, torpedo, rocket, or other munition which contains either the nuclear or thermonuclear system, high explosive system, chemical or biological agents, or inert materials intended to inflict damage. 

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