butt-fucking vs keister

butt-fucking

noun

  • anal sex 

adj

  • Engaging in anal sex 

keister

noun

  • The anus or buttocks. 

  • A suitcase or satchel. 

verb

  • To conceal something in one's rectum 

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