cop a feel vs maul

cop a feel

verb
  • To stealthily fondle someone in a sexual manner. 

maul

verb
  • To handle someone or something in a rough way. 

  • To beat with a maul. 

  • To criticise harshly. 

  • To savage; to cause serious physical wounds (usually used of an animal). 

noun
  • A heavy long-handled hammer, used for splitting logs by driving a wedge into them, or in combat. 

  • A situation where the player carrying the ball, who must be on his feet, is held by one or more opponents, and one or more of the ball carrier's team mates bind onto the ball carrier. 

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