It's when he shakes his (noble - I have to admit, it is noble) head, and the slobber flies off in every direction, and no matter how much you wipe up, there is always some you miss, and find dried rock solid on the wall, ceiling, lampshade . . .
The worst thing that happened (don't read this is you are eating, folks) was once when I was sitting watching telly, and he came over to me and stood right in front of me.
I said, "Shift yourself, Big Lad" and slapped him on the rump. Well . . . his anal glands must have been chock full of . . . whatever it is that anal glands get chock full of, and just my brief slapping action, which pushed his tail against his bottom for a microsecond, caused them to EXPLODE!!!!!
There was . . . . stuff . . . the foulest smelling stuff you could possibly imagine - made fox poo smell like Chanel No5 - ALL OVER THE WALL. It was flock wallpaper, too. I've never encountered ANYTHING so rank! (And I've owned four windy staffies) Really, really awful. We could get neither the stench not the stain off the wall, and had to take the paper off. It has scrubbable paint on it now.