Never heard of that towel trick, Vic... In the adopted greyhound world, when we talk about towel tricks, we mean take a hand-towel and pin it around yon male parts so that when he lifts his leg, rather than marking the wall (or bookcase, or my video collection or recliner, etc), he marks the towel instead. Wearing a wet towel is fairly uncomfortable, as you can imagine, and the dog quickly learns not to do that indoors.