BOB vs petting

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. 

petting

noun
  • The act of kissing, stroking, etc., a person in a sexual manner. 

  • The act of stroking or gently patting an animal. 

  • The act of indulging or treating as a favourite. 

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