lip service vs muff diver

lip service

noun
  • Cunnilingus (sometimes also referred to as giving lip). 

  • Promising but empty talk; words absent of real action or intention. 

muff diver

noun
  • One who performs cunnilingus. 

  • A lesbian. 

How often have the words lip service and muff diver occurred in a corpus of books? (source: Google Ngram Viewer )