necking vs smooching

necking

noun
  • A behavior among male giraffes where they hold combat for social dominance using their necks as weapons. 

  • Making out; kissing profusely, especially on the neck. 

  • Chugging beer. 

  • A neckmould. 

smooching

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