ball bag vs sporran

ball bag

noun
  • The scrotum. 

sporran

noun
  • A small pouch, usually made of either fur or plain or fur-trimmed leather, which is worn, suspended from a belt or chain, on the front of a kilt and used to hold various items normally carried in trouser pockets. 

How often have the words ball bag and sporran occurred in a corpus of books? (source: Google Ngram Viewer )