Stop It. Meaning/Usage: To ask someone to stop what they are doing.
Explanation: This is a common way of telling a person to stop something that is bothering you. It is more aggressive way of say, please dont do that.
1-Please stop it! You're giving me a headache.
2-Stop it before you get hurt!
3- You had better stop it or you will get in trouble!
Conversation
A-Tommy! Stop it right now!
B-Why? I saw other kids doing it.
A-That's not how we behave in a restaurant.
B- OK, I'm sorry.
Other Common Sentences
Quit what you are doing.
Don't do that!