Have you ever looked at those images of the proper typing position? It's some weird guy sitting straight up with his elbows bent just so and his wrists arched just right and who the heck has ever written a novel from this position? I've had one knee up, both legs crossed, two feet propped up and I'm not at all above completely laying down while typing. How do you write...and how strange are you for doing it that way?
According to legend, Virginia Woolf wrote standing up. It's because of a lifelong rivalry with her sister, who was an artist. Virginia didn't want her sister to say she had the more difficult job. There are lots of weird ways to write. Do you use one of them?
Jack Kerouac wrote all of On the Road on pieces of paper he taped together to create one massive scroll. This method actually did have a function, as odd as it sounds. Using one sheet of paper allowed him to work quickly without changing the paper in the typewriter. It's just too bad he didn't have Google Drive.
James Joyce wrote in a white coat with crayons. Much of Finnegans Wake was written on cardboard. Joyce wrote in bed while lying on his stomach, and all of this sounds incredibly weird. However, there was a reason for all these oddities. Joyce was practically blind, so the thick lines of the crayons made it easier for him to see his words. The white coat reflected light that helped to illuminate his writing.
Some writers write strangely, but often there's a reason for what they're doing. You have it pretty easy as an author today. Digital devices and cloud storage allow you to access your books from anywhere, so you can develop all sorts of quirks of your own. Write on the subway, while walking in the park, from the top of a building if you want. But put yourself and your body in a position that feels comfortable to you. There should be no straining nor stretching, no discomfort (unless you stay in one position for many hours; even a comfortable position can cause some pain when this is the case). And above all, you should pay attention to your wrists while you write.
Don't be quirky just to do it. Be comfortable while you write, and if you develop some weird habits then so be it. Do whatever you need to do to stay creative while keeping your body healthy. And when someone asks you how you write, say like a pro.