Well, she's not really in her birthday suit--more like an outfit my friend Jen made me for my birthday. Rather inspired by the 1980s, I have to say!
The cocktail dress is a cotton/silk blend, and shiny, with an attached black tulle petticoat skirt for fullness. Her lacey fingerless gloves are a bit tricky to put on--but with bendy-wrist dolls, a down and dirty trick is to pop the hands off first, slide the gloves on, replace the hands, and then pull the thumbs back over the hands. Her tights are heavy stretch lace as well.
The model, by the way, is Sydney on the Rocks, and her shoes happen to match perfectly.