crease up vs piss one's pants

crease up

verb
  • To laugh (or make someone laugh) uncontrollably. 

  • To become creased. 

piss one's pants

verb
  • To laugh uncontrollably. 

  • To be extremely frightened. 

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

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