Because why should cat lovers have all the tissue-from-butt tugging fun, this is the Digging Dog Butt Tissue Holder available from WhatOnEarth (still just as valid a question as it was for the cat version). It costs $28, covers a standard square box of tissues, and is sure to be a smash hit during the white elephant gift exchange portion of my girlfriend's ultra-fancy office holiday party this year (she thinks I'm bringing a foot massager!).
Keep going for a couple more shots while I speculate if they couldn't have made it look less like a giant turd somebody tried to futilely wipe.
Thanks to Christina D, who agrees it's only a matter of time until tissue dispensers are available in every animal butt design.