form a crocodile vs straighten up

form a crocodile

straighten up

verb
  • to start living a reformed life 

  • to sit up straight, to stop hunching. 

  • to steer straight 

  • to tidy; tidy up 

  • to deal with; put in order 

  • To become straight, or straighter 

  • To clarify 

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