lovebird vs snog

lovebird

verb
  • To express romantic affection openly. 

noun
  • Any small parrot from one of the nine species within the genus Agapornis. Sometimes they are kept as cage birds and are noted for their affection towards each other. 

  • One of the members of an openly affectionate couple. 

snog

verb
  • To kiss passionately. 

noun
  • A passionate kiss. 

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