The fabric is a polyester knit. Normally I would avoid poly fabrics like the plague, but this one was the only one that was the right color, and it actually feels surprisingly good against my skin. Normally polyester makes me sweat, but this one is okay.
The pattern is Butterick 6031. I love the Patterns by Gertie. On her blog, Gertie's Blog for Better Sewing, she does a sew along of this slip and it was very helpful. I skipped doing the lace around the top, under the bust, and along the hem, although I did still use lace for the straps. I did use picot elastic along the top so that there was still something to give it a little structure.
The pattern actually has instructions for doing adjustable straps, like on a bra. I made them that way the first time, but using the measurements as called for in the pattern left them inches too short. By the time I got around to redoing the straps so that the slip lay correctly I was feeling impatient so I just cut the lace to the right length for me and sewed it on. I don't feel like I'm missing out on anything by not having adjustable straps.
The other thing to note with this pattern is that you really do need to follow their instructions for determining your cup size. In a normal bra I'm a DD, but with this pattern I used the pattern pieces for a C cup and it fits perfectly, so don't assume that you can skip that step and just use your normal cup size (and oh boy does it feel like oversharing to say that, but I think it's important to know).
Because the fabric is a knit (and I was being lazy) I didn't bother to hem the bottom. I've got enough lace left from the straps that I might add it, but then again, probably not. I don't really like lace on my slips because although it looks beautiful it can cause the fabric of whatever I'm wearing over the slip to catch and stick, thus defeating the purpose of most slips.
Someday I would love to make another of these with all the lace because I do think it looks pretty. When I do that though I will probably being making it with intent to wear as pajamas. This slip is way super comfy and I could happily sleep in it.
Oh, and if you know what I quoted for the title you get extra special geek points. :)