Is it normal to wipe one’s arse standing up?

I do on occasion

If I do a really nasty shit and it takes a lot of wipes, I tend to try many different methods at once, e.g:
Wipe with right hand sitting down, left hand sitting down, right hand standing, left hand standing, leaning over to the side while sitting, sometimes I even go back to front but usually only on the last wipe. Occasionally if it seems like a losing battle, I'll just squat in the shower and wash it out instead

Only if its one's ass and not two's

I like to wipe standing up then I just dump the paper on the floor in public toilets

Yes usually I stand up. The toilet in my dorm is microscopic so I literally cannot wipe my fat ass while seated.

Normal, and much easier than wiping while sitting. Plus it's probably better for you since it gives you some squatting exercise.