piss one's pants vs snicker

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. 

snicker

verb
  • To utter through a laugh of this kind. 

  • To emit a snicker, a stifled or broken laugh. 

  • To whinny. 

noun
  • A stifled or broken laugh. 

  • A player who snicks the ball. 

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