If my child acted this way, I would stop her, hold her shoulders. Look her in the eyes and say, "listen to my words. You do not eat other peoples food. If you do this again we are leaving the party. "
"I want you to stop running. There are too many people here, to be running around like that. "
"Please repeat what I just said" Then she would need to repeat the whole thing back to me.
IF she did this again, we would leave. I would not say anything to her in the car. At home I would sit her down with my hands on her shoulders, look her in the eyes and ask her "Tell me why we had to leave the party?" Then she would tell me.
Then I would tell her, "I am disappointed we had to leave the party, because you would not do what I told you to do. . You will now not get to read the books (that was our daughters thing) you chose for this weekend to read.."
Or "you will not be allowed to play outside with your friends for the rest of the day.".
At another time, when she was in a quiet mood, maybe in the car.. I would then ask her.
"I want to know why when we were at Sam's party, you kept eating peoples food?" "Do we have a rules about how we behave at parties?" "What are the rules?"
"How would it make you feel if someone was taking your food off of your plate?" "How would it make you feel if someone did that to my / mommies plate?"
I also always had a discussion about what the expectation of behaviors were before we went to any event.
This party is at Sam's house. "If we are inside, how do we act? "
"If it is outside how do we act in someone else's yard?" we share the outdoor toys. We ask permission to take inside toys outside, we are careful with other peoples toys, etc..
"If they offer snacks, what do we say?" Thank you, please. Throw away our plate.. etc. Do not walk around with the food.. etc.. In this case you would have him say, not take peoples food.
"What do we do when it is time to leave" She knew this meant help clean up, tell the hostess and host, birthday child thank you for inviting me. "
Tantrums have always been zero tolerance with us.. The moment our child threw a tantrum, we removed her from the situation and told her. "You are in time out for 5 minutes. If you do not sit there quietly for 5 minutes we are leaving.."
Or I would have placed her in the car in her car seat, (turn on the air conditioning) and made her stay in there for the time out.. Me on the outside of the car. IF it continued, we would leave.
Our daughter learned very early on.. We do not do tantrums or fits. EVER.
Running off when you are walking..
Before you leave for the walk you talk about expectations of behaviors.
"You will walk with us, holding our hand. " or "You may walk in front of us, but we need to be able to touch your head with our hand. " "What did I just say/" What will happen if you run off? " Yes, we will go home and you will not be able to play with...
If he runs away or does not follow the rules..
You catch him and take him home for a time out.. End of the walk..
Later discuss your disappointment about his behaviors.
MOM, he is totally testing you guys. He knows he can get away with these behaviors. You need to love him so much, you will not allow him to act like this. be stronger than him and make him follow the rules of behaviors.
If they have tested him, then this is just his personality and he needs to be taught, you are stronger than him.. and he cannot wear you down.. No matter how many times, you must stick with the rules. Place it back on him, if the fun has to end. Better to do this now at 3 than in the future when he is a teenager and too big to control.