heavy date vs love nest

heavy date

noun
  • A date the stakes of which are high; a date in which both people are very invested. 

love nest

noun
  • A residence, especially a condominium or cabin, where a couple (particularly a newly cohabiting/married couple) can enjoy each other's company. 

  • The vagina. 

  • A place suitable for or used for having sexual intercourse. 

How often have the words heavy date and love nest occurred in a corpus of books? (source: Google Ngram Viewer )