Spill words are the things people "just" keep themselves from saying. Like it's on the tip of their tongue but they know it will get them in trouble so they don't say it.
"It was nice to see you"
-Will you just leave already-
"I have no idea what you're talking about."
-Do you really think I'm going to tell you where they are?-
She doesn't always hear them. So feel free to say you don't want her to. But if you want you can add spill words in your conversations with her.