If you’ve ever sent an email and instantly regretted it, this is the button you’ve dreamed of.

Google Labs is testing an “undo” button on Gmail that gives you 30 seconds to stop an email from reaching your boss, your husband or your soon-to-be-former best friend.

Being a Google Labs feature, it comes with the caveat that it “may break at any time” or “disappear temporarily or permanently.”

“Undo send” is one of a dozen or more experimental features Gmail users can try out by burrowing into the Settings page on the Gmail Labs website and enabling the feature.

The feature, which could also be called the “second thoughts” button, used to give you only five seconds to rewrite your personal history. Now you can tailor it to just how skittish you’re feeling each day.

The new device comes on the heels of a “survey” by one PR company for another PR company for 20th Century Fox Home Entertainment U.K. to promote the release of the DVD of the TV movie Going Postal.

The survey, picked up by several newspapers in the U.K. and India and dozens of websites, contends that one in five people have made an embarrassing email gaffe at work, and one in 20 were reprimanded or fired for that blunder.