go ahead vs save it

go ahead

verb
  • Used to grant permission for or to give endorsement of a suggestion or proposal. 

  • To proceed with; to begin. 

  • To send communication over the radio. 

save it

verb
  • Do not bother with the explanation that you are about to give; be quiet. 

How often have the words go ahead and save it occurred in a corpus of books? (source: Google Ngram Viewer )