BOB vs coin slot

BOB

noun
  • Vibrator (device designed to stimulate a woman's genitals). 

adj
  • Back-of-the-book; denoting those stamps in a catalogue that are not used for the payment of regular postage fees, and are displayed separately in the catalogue after that listing; the division between these two groups varies with the publisher. 

coin slot

noun
  • Vagina. 

  • A small opening on a vending machine, arcade game machine, parking meter, etc. to accept the payment that operates the mechanism. 

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