bung-hole vs butt-fucking

bung-hole

noun

  • The anus. 

  • A hole in a vessel, such as a cask, that may be stopped with a bung. 

verb

  • To have penetrative anal sex with. 

butt-fucking

noun

  • anal sex 

adj

  • Engaging in anal sex 

How often have the words bung-hole and butt-fucking occurred in a corpus of books? (source: Google Ngram Viewer )