honey hole vs tunnel of love

honey hole

noun
  • A vagina or vulva, as an object of sexual interest. 

  • A location or situation which yields something of significant value. 

  • A hole in the trunk of a tree, containing the natural honey produced by a colony of bees. 

tunnel of love

noun
  • The vagina. 

  • A carnival dark ride for couples in boats, either relaxing and romantic, or spooky (encouraging the couple to cling to one another). 

How often have the words honey hole and tunnel of love occurred in a corpus of books? (source: Google Ngram Viewer )