It's incredibly simplistic, really. "Walzen" used to detonate the act of spinning in old German. A simple name for a dance that was initially perceived as low class and obscene because of the amount of physical contact between dancing partners. Of course, it very quickly established itself in the upper circles anyway.

[ She chuckles a little. ]

This was back in the day when the idea of an ankle showing under a woman's moving dress was scandalous. With your long gown, you might be safe from even the indecency of that time though.