kid stuff vs lastborn

kid stuff

noun
  • Something done by, used by, or characteristic of immature people, especially children. 

  • Something that is easy to do or easy to understand. 

lastborn

noun
  • The youngest child of a family. 

  • The youngest member of any company or organization. 

adj
  • Born last in a family; youngest in a the family. 

  • Younger than anyone else in a group. 

How often have the words kid stuff and lastborn occurred in a corpus of books? (source: Google Ngram Viewer )