Donkey Back Rider

All right...so the first person to explain to me how this dog perfectly balances himself whilst asleep on this donkey gets a shiny new donkey. Also, at what point do you figure that the dog fell off as the donkey strutted about? And if there are horoscopes for dogs, are there horoscopes for donkeys too? According to Google, no and I'd like to keep it that way, thank you.