Before I continue with other stories, some general thoughts on cultural differences:
As I said, I'm from Austria. Here - and it's the same in Germany and Switzerland - being naked is not something unusual.
As I am reading stories from other folks here, I'm wondering about some things: Especially when somebody tells about a father who was naked in front of his daughter...well thats something completely normal here. Many families don't bother being naked in front of each other.
The same thing applies in Saunas, Spas, Beaches: It is very common to be naked in front of strangers. Especially in saunas. Going topless at the beach etc. But unfortunately, it is not very common, to be naked in front of friends, in-laws etc.
And this is the point which is exciting for me: I am definetely voyeuristic and a little bit exhibitionistic. The best thing for me is to see somebody naked I know, e. g. female friends, co-workers etc. Most stories so far dealt with this topic and some further stories will.
What's your opinion on that? I guess, most people here are US-based. Is it really something special to you, to see your sister naked? Or to watch a naked family?