This is going to be one of the simplest posts I’ve ever done, as this was one of the simplest projects I’ve made.
After cutting out my stay mock up pieces I had a lot of cotton scraps left, so I found the biggest piece I could and folded it in half. Miraculously it was about the same length as my upper hip measurement (minus about 1″ which was good because you need a gap for tying the ends together)
I then folded this piece in half horizontally so I had a quarter. Then you need to cut a curve, just do it by eye, the top image is a general guide for the cutting pattern, the bottom image the rough sort of shape you should end up with.
Once you’ve done that sew the curved sides together, make sure to sew a ribbon firmly to either end, placing the ribbons inside the tube as you sew. Leave a gap 5 cm wide at the minimum, turn right-side out and stuff with your choice of stuffing- I used fabric scraps but you could use batting as well. Then sew the gap closed by hand and try it on!
It is important to note that this is a method for a fairly small bum-roll and there are better methods for more lift. It’s also important to note that you may need to come back to the bum-roll and add some kind of frill or ruffle in order to make the line of the skirt smooth. You could use tulle if you don’t care about historical accuracy, or lace if you only need a bit of extra lift. Historically speaking you should probably use cotton like these examples. Originally (left) my petticoat had a very shelf like appearance, but then I lowered the placement of the roll (I’d put in round the waist) and added a ruffle (right) and it fell nicely (bottom). This didn’t change the front profile (middle) at all which I was already happy with.
As I said, nice and simple plus uses up all the scraps that were beginning to take over the sewing room!