sex up vs spark up

sex up

verb
  • To make more sexually attractive. 

  • To enhance in terms of fashionable appeal. 

  • To sensationalize. 

  • To arouse somebody sexually 

  • To take part in sexual acts with. 

spark up

verb
  • to make more exotic or fun 

  • To provide electrification. 

  • To initiate (a conversation, debate etc.) 

  • to rekindle 

  • To light up; light a cigarette or start smoking a pipe, bong, etc. 

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