Use the adverb imperiously to describe a manner that is domineering and authoritative. Shouting, "Sit! Stay!" imperiously might work well on the dog, but it won't necessarily work on your friends.
Imperiously comes from the Latin word imperare, which means "to command." Other words from this same root include empire, emperor, imperial, and imperative. Like imperiously, all of these words retain some sense of command in their definitions. When you were three, you might have imperiously announced to your toys that they must come to life immediately, or you would banish them to the dark wasteland known as the closet.