prat vs tail end

prat

noun
  • A buttock, or the buttocks; a person's bottom. 

  • A cunning or mischievous trick; a prank, a joke. 

  • The female genitals. 

  • A fool. 

tail end

noun
  • The hindmost part of anything (a person, animal, or object), the rear end; the butt, buttocks; hindquarters, rump. 

  • The last part of a period of time, event, or situation; the concluding or final part. 

How often have the words prat and tail end occurred in a corpus of books? (source: Google Ngram Viewer )