coin purse vs stepchildren

coin purse

noun
  • A small bag or pouch designed for carrying money, particularly coins. 

  • Testicles. 

  • a type of theatrical performance undergarment used to hide male genitalia, by stuffing it into a pouch with a drawstring, to simulate being nude 

stepchildren

How often have the words coin purse and stepchildren occurred in a corpus of books? (source: Google Ngram Viewer )