I'm not sure who it was that first told me of slounging (it might have been Shrift, and if you aren't lucky enough to know or know of Shrift, well, someday you'll hear stories), but this is a dress for it. Most slounging (which is, of course, a blend of 'slouching' and 'lounging') takes place in a seated position, of course, but for those rare times when you have to project a languid slounge standing up, you need a dress like this.
I think it's because the hips are pushed forward and the shoulders rounded, but it just might be because of those little cuffs on the sleeves. The sloungability quotient of this dress is only heightened by the air of complete and utter indifference that these women are projecting. It's impossible to care and slounge simultaneously.
The woman in the red version is slounging so expertly that she's not even facing you. But she's still saying "Darling, get me a drink, won't you? Lots of ice." She likes lots of ice because her bracelets and the ice clink in a slightly different ways, and the dissonance sets you even more on edge.