play with fire vs whistle past the graveyard

play with fire

verb
  • To put oneself in a precarious situation with a high risk of getting harmed, particularly emotionally or financially. 

whistle past the graveyard

verb
  • To enter a situation with little or no understanding of the possible consequences. 

  • To attempt to stay cheerful in a dire situation; to proceed with a task, ignoring an upcoming hazard, hoping for a good outcome. 

How often have the words play with fire and whistle past the graveyard occurred in a corpus of books? (source: Google Ngram Viewer )