kissing cousin vs maternal cousin

kissing cousin

noun
  • A relatively distant relative, or a friend, who is familiar enough to be greeted with a kiss. 

  • A thing which is related or similar to another thing. 

maternal cousin

noun
  • A more distant relative of one's mother who is not a direct ancestor 

  • A child of one's mother's sibling 

How often have the words kissing cousin and maternal cousin occurred in a corpus of books? (source: Google Ngram Viewer )