goatskin vs penile sheath

goatskin

noun
  • A liquid container (especially of wine or water) made from goat leather. 

  • a bodhran drum. 

  • The skin of a goat. 

penile sheath

noun
  • A device fitted over the penis that is connected to a drainage bag, used to assist with urinary incontinence. 

  • The foreskin. 

How often have the words goatskin and penile sheath occurred in a corpus of books? (source: Google Ngram Viewer )