beat off vs beat one's meat

beat off

verb
  • To waste time. 

  • To drive something away with blows or military force. 

  • To masturbate, usually a man of himself. 

beat one's meat

verb
  • To waste time; to engage in an unproductive activity. 

  • To masturbate by stroking or rubbing one's penis. 

How often have the words beat off and beat one's meat occurred in a corpus of books? (source: Google Ngram Viewer )