have a laugh vs piss about

have a laugh

verb
  • To laugh. 

  • To joke; kid around. 

  • To enjoy oneself; have fun. 

piss about

verb
  • to joke or play 

  • to misbehave; to act foolishly 

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