I think he was telling her "no Sadie", but it could have also been "go away Sadie" or "stay down Sadie". He likes to pretend that he is her boss. She likes to let him pretend that he is her boss.
Now we get down to the mad chase around the trailer. Kyle says "Comeeeeere Sadie. Come on Sadie. Comeeeeeere Sadie" and then he runs. The only reason Sadie actually follows him is because he has her toy. Again.