Made famous by dancing guy on It's Always Sunny in Philadelphia. It's when you wear a diaper and possibly other baby accessories while dancing to some club/techno but be so cool people dig that you're in a diaper.
When Dancing Guy was on public access in It's Always Sunny in Philadelphia diaper time came at random intervals of the show introducing people dancing without a care just in their diapers.
by Bob Loblaw Law Blog Foundation June 15, 2010
Marking a sudden change in events, in which all common sense and rational thought are replaced by a relentless pursuit fueled by deep emotion or obsession, often involving traveling long distances, and often with violent intent.
When that astronaut realized that another woman was moving in on her man, she made up her mind to drive 900 miles non-stop and kidnap her. It was diaper time.
by Tich2 February 10, 2007