(I usually write a small exploration of the issue, here, but in this case I don't dare.)
(I've put this photograph in for fun, even though this sort of a bustle is a completely different word from the one we're thinking about.)
Thing To Do Today: bustle. This word appeared in the 1500s. perhaps from buskle, which meant to make energetic preparation, from the Old Norse būask to prepare.
I suppose the masculine equivalent is hustle, isn't it?
This is possibly an even scarier thing to think about in print, so I think I'll shut up.
The origin of the padded-bottom sort of bustle is, sadly, an eighteenth century mystery.