open one's mouth vs spill one's guts

open one's mouth

verb
  • to speak 

spill one's guts

verb
  • To confess, or to divulge secrets, typically speaking freely and at length after a change of motive or an incentive. 

  • To vomit. 

How often have the words open one's mouth and spill one's guts occurred in a corpus of books? (source: Google Ngram Viewer )