Also used to describe a chic restaurant or bar frequented by "beautiful people" (esp. media/fashion/art types), when it is often shortened to a single "mwah"
An evil laugh. A laugh one does when they are about to do something evil. Such as when a villan has a plot to take over the world, he does this laugh right before it goes into effect. Also a noise made by people who have just gotten away with an evil deed or crime.
12 step recovery jargon referring to someone new who talks about how great life is, now that they'resober. Usually meaning that the person is out of touch with reality.
The new guy seems pretty happy for a dude who has no job, no money and no family. He must be on a pink cloud.