arouse vs spark off

arouse

verb
  • To sexually stimulate. 

  • To stimulate or induce (feelings). 

  • To cause an erection of the penis or other physical signs of sexual arousal, such as fluid secretion. 

  • To wake from sleep or stupor; to rouse. 

spark off

verb
  • To initiate something by providing the necessary conditions. 

How often have the words arouse and spark off occurred in a corpus of books? (source: Google Ngram Viewer )