lol! It is a process, isn't it? Probably could be a whole other thread.
When I bought my dry suit it was such a struggle for me to get my second arm into the suit. I asked the company rep (this was a direct purchase from Ocean Rodeo) and he said, "I find it helpful to hop up and down on one leg while swearing loudly." And sure enough, that did the trick. I've gotten much more flexible since those early days: now, I can now swear silently as I hop up and down on one leg and still get my second arm into the suit. Eventually.