front bum vs tunnel of love

front bum

noun
  • The vagina or vulva. 

  • A bipartite mass of abdominal fat. 

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 front bum and tunnel of love occurred in a corpus of books? (source: Google Ngram Viewer )