I ride with a friend who has a certain affinity for dogs – or, to be precise, dogs hate him and want to eat his soul. He wears big leather boots and if an aggressive dog tries to bite him (which happens more often than you might think!) then he kicks them. Modestly, at first, but if they come back for a second go, they’re going to get punted into the next field.
Sorry, if you can’t control your dog, it’s gonna get a paddling!
(Incidentally, every time this has happened, the owner has always thanked him for being so patient and confirmed that they would have kicked the thing too!)