bone-on vs lead in one's pencil

bone-on

noun

  • An erection of the penis. 

lead in one's pencil

noun

  • A state of erection of one's penis. 

  • Used other than figuratively or idiomatically: see lead, pencil. 

How often have the words bone-on and lead in one's pencil occurred in a corpus of books? (source: Google Ngram Viewer )