be petrified vs piss oneself

be petrified

piss oneself

verb
  • To wet oneself. 

  • To laugh uncontrollably (to the extent that one might lose control of one's bladder). 

  • To be very scared (to the extent that one might lose control of one's bladder). 

How often have the words be petrified and piss oneself occurred in a corpus of books? (source: Google Ngram Viewer )