set tight 在美俚语中的含义

In slang, there's no such phrase as "set tight", but if u mean "sit tight", it would be to brace yourself for something to happened, or it could just simply mean to sit comfortably.
So you will be sit tight when teachers are handing out exams.

安排紧凑
系紧
原地不动

可以查一查牛津词典