hair pie vs muff diving

hair pie

noun

  • Cunnilingus. 

  • The external female genitalia with an unshaven mons veneris. 

muff diving

noun

  • Cunnilingus. 

adj

  • Performing cunnilingus; that performs cunnilingus. 

How often have the words hair pie and muff diving occurred in a corpus of books? (source: Google Ngram Viewer )