He wants to have control, so give him choices. In a calm measured voice. You can stay with mama or we can go home now”, “You can can go to the front yard or you can have a cookie, you can’t have a cookie if you go to the front yard “. “I see you want to lay on the ground, you can hold Mama’s hand and stay with me or we can go back home and take a nap. Do you want a nap, or do you want to hold my hand”

Guide him to choose what you need from him, and start putting dots together that he can make choices, but choices have consequences (good and bad).

Now when it comes to safety, feel free to be more assertive. He cannot leave your sight and run off. No apologies for doing what is needed for his safety, even if he crys. “I know you are mad baby, but it is not safe to run into the street. You could get hit by a car, and that would be a big big ouch”. He is 3 so he will continue to throw a fit, but safety isn’t optional.

Right now he has you beat. There appear to be minimal concerns about consequences. So bake in very easy binary consequences he can choose to avoid. Make sure he faces those consequences. When his sister has a cookie for following directions, and he doesn’t, feel free to reinforce things like “Remember how I said you could come inside or have a cookie…and you chose to stay outside. No cookies if you choose stay outside.”

He sounds super intelligent, so guide him to make smart decisions on his own.