drop a bomb vs move one's bowels

drop a bomb

verb
  • To release feces into a toilet; to defecate. 

  • To release noxious gas from the bowels: to fart. 

  • Used other than figuratively or idiomatically: see drop, bomb. 

move one's bowels

verb
  • To excrete feces from one's bowels: to defecate. 

How often have the words drop a bomb and move one's bowels occurred in a corpus of books? (source: Google Ngram Viewer )