jack off vs wank off

jack off

verb
  • To masturbate. 

  • To stimulate or please oneself in an unproductive or idle way. 

  • To manually stimulate someone sexually, generally a male. 

wank off

verb
  • To masturbate. 

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