The system works like this:
Submissions go into the CMS. I delete any rubbish and duplicates and approve any new idioms, possibly changing words here or there, or adding definitions where people have only put the idiom. Then they will appear in the section. You can check here
http://www.usingenglish.com/reference/idioms/new.html to see if it's there; I don't contact because this area is not part of the forum and anyone, member or not can submit.
There will often be a time lag of up to a day depending on where people are in the world- I am on Cambodian time and generally check in the afternoon. If it's a new idiom, I will always include it, though it could also go into the slang database if that is more appropriate. I may change the wording a bit, though that is generally when learners submit.
