fire-crotch vs gingernut

fire-crotch

noun
  • A person who has red pubic hair. 

gingernut

noun
  • A redhead; a ginger-haired person. 

  • A hard biscuit, flavoured with powdered ginger, often dunked in tea. 

How often have the words fire-crotch and gingernut occurred in a corpus of books? (source: Google Ngram Viewer )