An excuse for anything, whether someone lost in a game or did something stupid, it can be used whenever. No dogs have to be present nor does anything play part in the mishap, it is simply a phrase meant to be used when you want to make an excuse or a defense for something. Originated from Simi Valley
John: I wrecked you in basketball! You suck!
Nico: The dogs were barking! That was it!
John: Mhm sure they were!
Greg: Haha how did you trip on that rock?
James: The dogs were barking, so I didn't see it!