BOB vs la-la

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. 

la-la

noun
  • A woman's genitals, especially the vagina; a sexually permissive woman. 

  • Something unusually good; (occasionally) something unusually bad. 

verb
  • To sing or recite the syllable la repeatedly. 

  • To sing (a song) with la replacing the song lyrics. 

adj
  • Of indifferent quality; so-so. 

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