Behind closed doors

What you do with your girlfriend behind closed doors is none of my business.

Miss Maudie shook her head. “If he’s not [crazy] he should be by now. The things that happen to people we never really know. What happens in houses behind closed doors, what secrets-”

A brilliant piece of undercover reporting revealed extraordinary details of how senior City executives behave behind closed doors.

A major problem has been the making of bad decisions behind closed doors.

Libya's opening home match in the World Cup qualifiers against Cameroon will be played at a neutral venue and behind closed doors, FIFA said on Friday. https://web.archive.org/web/20150611004158/http://in.reuters.com/article/2012/04/20/soccer-world-libya-idINDEE83J07G20120420

In other research, scientists have found that people who kept cereal out in the open were often about 20 pounds heavier than people who kept cereal behind closed doors.