A while back I bought and downloaded this pattern, which includes a pattern for a bustle pad or pillow. So finally, before my last event, I decided to try the bustle pad and see if I liked the effect.
I did. Having an actual bustle extension changes your shape, adds Victorian authenticity, and makes those floofs pop. I thought my ass was already big enough. Turns out I was wrong. So what's under that skirt?
It's construction is pretty simple. The bottom, as you can see in the second picture, is a half-oval. The front and back are two trapezoids, one bigger than the other. The smaller trapezoid is the back, the side against your body. The larger trapezoid is gathered along the top (smaller) edge so that it is the same width as the smaller trapezoid. The bottom of the large piece is the same length as the curve of the half-oval. Right sides together the large side of the front is sewn to the curve of the half-oval. The straight side of the half-oval is sewn to the larger side of the smaller trapezoid, and the sides of the two trapezoids are sewn together, leaving the top open. The pillow is stuffed with stuffing and then a waistband is added to the top to seal it up.
I made a bad Paint drawing of the pieces for the pillow. These are just free-drawn. They are not to any exact scale and aren't a real pattern, but a visual aid to help you make your own and understand what I'm describing above.
As for the size of the pillow, that depends on your size and your build. If you're very curvy already, like me, you'll want a bigger bustle so it looks proportionate on you. If you're a flatter shape, that's probably going to look a little weird on you, so you'll want a smaller bustle. The width of my back piece at the bottom is 14" without seam allowance. At the top it is 10." The bottom of the front piece is 18". The height is around 9", including the waistband. You want it to be smaller than the width of your behind and you ideally want it to rest on top of your own curves. As for stuffing, you can probably tell mine is a little under-stuffed. I didn't know how it would look, and I was afraid of having a horribly overstuffed thing coming out of my back. And it's deflated a bit from having been worn to two events and sat on etc. So you may want to add more stuffing than you think you should, knowing it will compress some.
As for the waistband, I just made one with two buttons on it to button around my waist. It fits snugly when I put it on, but after I add my corset over the top, my waist shrinks a few inches and the waistband sags a bit. To avoid this, you may want to use elastic or a drawstring in your waistband to make sure your bustle stays where you want it. As for comfort, I've found wearing this to be really comfortable. I'm not aware of it feeling different than wearing my outfit normally until I sit down. And then it just squishes into the back of your chair like the rest of your skirts. You don't end up sitting on it, since it's on top of your behind. It's just a little more volume to take into account when sitting down. It kinda makes a good lumbar pillow, too, if it squishes just right.
One final note. At Aggiecon last weekend, one of the vendors (not in costume) complimented me on wearing a bustle as "it's something people leave out". I told her it was a bustle pillow and lifted up my overskirt to show her. She then spent a few minutes explaining to me how my bustle pad was wrong and how it should be in a different place and be shaped differently, etc. It sounded like she was describing a bum roll, which is the wrong period, but I just smiled and nodded and walked away as soon as I could. This kind of nitpicking on historical accuracy is so annoying. And it's not very steampunk (although I don't believe the lady in question was a steampunk). If the effect it produces under my skirts looks good (and it obviously did or she wouldn't have stopped me to compliment me), then I don't care if this is not the way it should look or not.
If anyone has any questions, feel free to ask. I hope this helps someone achieve the look they're going for.
EDIT: If you would prefer to work from a pattern, or want a different style/size of bustle pad, I now offer a downloadable pattern for three styles of bustle pad.