I write left-handed, do everything else right-handed.
Can kinda write right-handed... but its slow and messy.
I find im a terribly slow writer, i never get as much out in an essay as anyone else, that said, ive never studied in my life, and type everything possible.
My hand tends to cramp alot, say after half a period of straight dictation, but so far i havent had any trouble in exams.
The pen up the side of my hand is horribly annoying and may as well be permanently stained, but for some reason my writing itself doesnt get smudged much, and its large and easily legible.
I don't think i write upside down or sideways really... but i probably do without realising it, i was sitting "side saddle" as the examiner called it in AOS and got told to turn around to the front.. i had no idea i was even doing it.
Go figure.