raw dog vs uncover

raw dog

verb
  • To have sex without a condom; to bareback. 

  • To do an activity without protection or intermediary. 

adv
  • Without a condom; bareback. 

uncover

verb
  • To expose the genitalia. 

  • To remove one's hat or cap as a mark of respect. 

  • To reveal the identity of. 

  • To remove a cover from. 

  • To show openly; to disclose; to reveal. 

  • To expose (lines of formation of troops) successively by the wheeling to right or left of the lines in front. 

How often have the words raw dog and uncover occurred in a corpus of books? (source: Google Ngram Viewer )