n. A self-deprecating comment or story that acts as a brag because it shows the person is confident enough to admit a failing or embarrassment.
There are a lot of different kinds of brags: the humblebrag and the underbrag, for example. However, only one kind of bragging is not only acceptable, but encouraged: the shirtless brag.
The latest form of boasting is being called the 'underbrag' — whereby you tweet something so slovenly or shocking, it shows that you simply don't care or have to worry about losing your job/friends/partner.
What's the underbrag? That's when you brag your own disaster or situation that one would not normally brag about. Skilled underbraggers can get away with doing so because the underbrag is not fake like the brag brag.