Marmaduke and/or his owner-girl (and, either way, Marmaduke creator Brad Anderson by extension) are mocking the slang and crass consumerism of mainstream hip-hop culture.

(Speaking of crass consumerism, pre-orders for the "Marmaduke is an Asshole" t-shirt only have a week or so to go... After that, the free Joe Mathlete index card artwork offer is off the table, and you'll probably hate yourself forever. Why not head over to the pre-order page, which was created in haste and looks that way to boot)