Acronym for Bitching About It With You.
When two (or more) people disagree about how terrible something is, but want to rant at each other about it anyway.
Person 1: *posts a long rant about something*
Person 2: *posts an equally long reply bringing up different points*
Person 1: "Agreed! That's pretty much what I said!"
Person 2: "Yeah, I'm just baiwy."