Ass Crack of Dog Share definition Flag When your dog wakes you up at 5:00 AM with his butt in your face. I'm exhausted still after having woken up at the ass crack of dog... At least I had plenty of time to shower. Ass Crack of Dog by saffirepulse July 8, 2018 0 0 Get merch Get the Ass Crack of Dog mug. Buy Now — $32.95 See more merch