blacksnake vs cat-o'-nine-tails

blacksnake

noun
  • A long, tapering whip. 

  • A penis, especially a black penis. 

verb
  • To whip with a long, tapering whip. 

cat-o'-nine-tails

noun
  • A scourge (multi-tail whip) having nine, often knotted, whipcords, formerly used for flogging as naval punishment. 

  • A similarly constructed leather nine-tail whip, as used in British penal colonies and certain armies. 

How often have the words blacksnake and cat-o'-nine-tails occurred in a corpus of books? (source: Google Ngram Viewer )