fraternize vs rub elbows with

fraternize

verb
  • To associate as friends with an enemy, in violation of duty. 

  • To associate with others in a brotherly or friendly manner. 

  • To have an intimate or sexual relationship with a forbidden member of the opposite sex; as, in some cases, football players with cheerleaders. 

rub elbows with

How often have the words fraternize and rub elbows with occurred in a corpus of books? (source: Google Ngram Viewer )