Though not considered to be a “stinging” caterpillar, contact with the Fir Tussock caterpillar’s (Orgyia detrita) hairs can cause measurable irritation for some people. Fortunately, I’m don’t seem to be one of those people. I’ve had a bit of contact with two hairy tussock species, and neither resulted in any kind of irritation whatsoever. At the same time, I wasn’t exactly petting either caterpillar along the backside. They were crawling on me, and I assume the longer, needle-like “hairs” along the back are what you want to avoid contact with.
This species ranges throughout much of the American southeast — from Texas east to Florida and then north to New Jersey along the Atlantic coastline. In Florida, I can’t recall ever seeing there in Volusia county, but I have seen plenty of tussocks in north-central Florida (specifically in Alachua and Gilchrist counties).