"In bringing out his Molossi and whaffling Whelps, and crying, Stoo Dogs, stoo."
Pure Hunting of the Snark! Well, actually, a line from a polemic of 1698 called Christ Exalted and Dr. Crisp Vindicated. I ran across it in the OED and chortled with delight without the slightest idea what it meant.
I did some poking. Molossi are breeds of dog once used as war dogs. Like all breed histories, it's complicated; but think Mastiff, bulldog, and Great Dane. And "Stoo" is a word shouted to urge on hounds—which calls to mind, "Cry havoc, and let loose the dogs of war" (Shakespeare, Julius Caesar III.1.273). I had always thought those bitter words were metaphoric, but it turns out that "Cry havoc" is the command given to an army to begin pillaging. Couple it with ferocious dogs and you have a fearsome, concrete depiction of something terrible.
But to return to the baffling quotation: "Whaffling" means yelping. Whelps are puppies, so perhaps there is an ironic coupling of the fierce and the foolish. I'm not going to plunge onto reading the jeremiad to find out, but I do hope that I can someday invent a character whose speech is half so colorful.
As for the image: I was unfamiliar with the Stuttgart deck of playing, which has hunting themes for the four suits. It just seems one more somewhat offbeat element to stimulate a quirky element in a story.