Good advice here. But question: do you know for a fact that this fire thing actually happened? The only way for this sort of thing to (possibly) have a positive long term effect on behavior is to include spanking right where she likes it best just for fun, but to push her limits when she dun fucked up. Like i looove being kicked, so its never a punishment, but when the rubber paddle comes out im like, aw fuck, this is gonna be torture, and while i still enjoy it in a way, i can only do so much before safewording. Im a huge fan of red yellow green for safewords, so if youre really looking to punish, aim for say, three yellows. Your/her mileage may vary.