cop a feel vs fool around

cop a feel

verb
  • To stealthily fondle someone in a sexual manner. 

fool around

verb
  • To engage in casual or flirtatious sexual acts. 

  • To engage in adultery; to play around. 

  • To waste time. 

  • To engage in frivolous behaviour; to monkey around. 

How often have the words cop a feel and fool around occurred in a corpus of books? (source: Google Ngram Viewer )