jerk off vs muck about

jerk off

verb
  • To do nothing; to waste time. 

  • To deceive. 

  • To masturbate, usually a male. 

noun
  • An act of masturbation. 

  • A stunt in which the performer is suddenly pulled off a horse, etc. by means of a cable. 

  • An annoying person. 

muck about

verb
  • To do random unplanned work or spend time idly 

  • To attempt to do something with a piece of equipment without understanding how it works. 

  • To be playful; full of fun and high spirits; to not treat the situation seriously. 

How often have the words jerk off and muck about occurred in a corpus of books? (source: Google Ngram Viewer )