roll on vs tip one's hand

roll on

verb
  • To snitch or tattle (on a person or group), to reveal a secret under pressure, usually regarding criminal matters. 

  • To pass; to go on; to elapse. 

  • To continue to move forwards. 

intj
  • Used to express anticipation 

tip one's hand

verb
  • To inadvertently reveal any secret, particularly a secret that puts one at an advantage or disadvantage. 

  • In card playing, to accidentally reveal one's cards or hand. 

How often have the words roll on and tip one's hand occurred in a corpus of books? (source: Google Ngram Viewer )