This dress is NOT "polyester sequin" material. At all. It's metal mesh (see pic). Which is really pretty neat. No, it doesn't seem to be uncomfortable, although I've only tried it on so far. This dress is all about the "drape". It's simply two lengths of metal mesh attached together. But seeing it come out of the bag, and seeing it on are two completely different things. The pics on the store site don't lie - it's quite attractive on the body! I don't see much in the way of options regarding underclothes. I tried it on with cotton panties, and the dress kept getting hung up on the material of the panties. I have no idea if Spanx, silk, satin (or some such material) would work under this - but going bare will definitely work! I believe there are supposed to be neck straps of 3 different lengths that come with it, so you can wear the dress any of the 3 ways shown. The two longer straps with mine are the same length (longest), so I will shorten one slightly myself to wear the dress how I want to (the length shown in the picture accompanying this review). The extra long one can be worn down the front of the dress as shown in the pics, but I may actually attach it to the neck strap and let it drape down my back. All in all, I'm very happy with this dress so far. It arrived within the specified shipping time with no issue, and I was able to follow its progress via the tracker they offered. The size was correct for the measurements given - but definitely pay the most attention to the waist size - the dress is forgiving everywhere else but there.