boff vs show someone one's etchings

boff

verb
  • to have sexual intercourse (with someone) 

  • To hit; to strike. 

noun
  • A great success; a hit. 

  • A pupil who works hard; a swot. 

  • A line in a film etc that elicits such a laugh. 

  • A big laugh. 

  • A hit or smack. 

show someone one's etchings

verb
  • A clichéd innuendo used to offer to bring someone to a private location in order to have sex, to show a place where people can engage in sexual intercourse (alternatively replacing "someone" with a phrase starting with to) 

How often have the words boff and show someone one's etchings occurred in a corpus of books? (source: Google Ngram Viewer )