pee vs piss one's pants

pee

verb
  • To urinate on oneself. 

  • To drizzle. 

  • To urinate. 

noun
  • The sliding weight on a steelyard. 

  • Urine. 

  • The name of the Latin-script letter P. 

  • An act of urination. 

  • Pence; penny (a quantity of money) 

  • The bill of an anchor. 

piss one's pants

verb
  • To wet oneself; to urinate in one's own clothes while they are being worn. 

  • To be extremely frightened. 

  • To laugh uncontrollably. 

How often have the words pee and piss one's pants occurred in a corpus of books? (source: Google Ngram Viewer )