dirty pillow vs milk jug

dirty pillow

noun

  • A breast, especially a woman's breast. 

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

milk jug

noun

  • A woman's breast. 

  • A jug for holding milk. 

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