dirty pillow vs maraca

dirty pillow

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

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

maraca

noun
  • breasts 

  • A Latin American percussion instrument consisting of a hollow-gourd rattle containing pebbles or beans and often played in pairs, as a rhythm instrument. 

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