knock it off
To stop talking about something considered not appropriate or nonsensical by the listener. Used frequently as an imperative.
Come on, Joe, knock it off, you're not making any sense at all!
To cease doing something; to quit. Heavily favored in the imperative.
Come on boys, knock it off, you're breaking the furniture in my room!
He kept bothering her, so finally she told him to cut it out. However, he wouldn’t knock it off until her larger brother appeared.