If I'm irritated or resentful, it comes on like a quick flash of red, as if to say, "Stay away from me!" But if that turns into frustration and pure anger... then I go cold inside. And it's not a good, soothing cold, but painful, like I'm being frozen from the inside-out, and the ice itself is searing my heart. I've also noticed that my voice gets deeper and hoarser if I'm truly feeling provoked and I feel less human and more like a beast about to be uncaged.
Fortunately for the rest of the world, such episodes tend to pass quickly for me, and I do my best to avoid conflict or smooth preexisting ones over whenever I can.