My usual reaction to pain is just to swear, which on it's own isn't that unusual, except I grind my teeth at night and sometimes I'll bite my tongue hard enough to make it bleed (as the tongue gets trapped and cut up in the gaps where I've had teeth removed) which makes me wake up in an instant, but before my mind has woken up.
This has cause me to utter some hilarious and creative variations of the words "****", "Shit", "Gay", "Bastard" and "Fuck" that could only be conjured up by the subconscious, dreaming mind, as I'm rudely torn into consciousness with a sudden sharp pain and bleeding tongue.
I'll be soundly and peacefully asleep one moment, then suddenly sit bolt upright with a cry of something bizarre like "Cuntylicious Fuckwranglers!" or "Shitbastard Gaynor Jr!". It's hard to remember the exact curses I utter as I usually go back to sleep straight after, but sometimes a particularly creative invention will resurface in my mind, later in the day.
I'd imagine this would seem very strange to an observer, who could be forgiven for thinking I suffer from night-Tourettes, but no, I just bit my tongue.