bubby vs dirty pillow

bubby

noun
  • A woman's breast. 

  • Familiar term of address for a boy; bub; bubba. 

dirty pillow

noun
  • A breast, especially a woman's breast. 

  • Used other than figuratively or idiomatically: see dirty, pillow. 

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