slit vs tunnel of love

slit

noun
  • The opening of the vagina. 

  • A narrow cut or opening; a slot. 

  • A woman, usually a sexually loose woman; a prostitute. 

verb
  • To split into strips by lengthwise cuts. 

  • To cut a narrow opening. 

  • To cut; to sever; to divide. 

adj
  • Having a cut narrow opening 

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