"Oh baby, a triple!" is a phrased coined by a child playing one of the Call Of Duty games. He happens to be wielding a sniper rifle during a round of ffa, and while camping comes across 3 people standing in a line. He fires, and headshots all 3 players, shortly after saying "Oh baby a triple! Oh yeah!" The term is commonly used among gaming communities, and it may be used as a literal term to describe a triple kill, or it would be used as sarcasm, to show someone their accomplishment wasn't very important.