Step 1: Cut your jeans off from the hem, taking as much as you want off, but leaving enough for the length you want and the hem. Then unpick the inner seam, leaving the outer seam alone. Also, unpick the seam going up leaving about 2" untouched from the zipper and below the pockets in the back.
Step 2: Fold your inseam part over like so and pin it on both the front and back. I find it's easier to sew this part first, then add your fabric in the middle, then it doesn't move while you are pinning.
Here what your seams look like from the inside.
Step 5: Now that you have your front and back sewn, now you need to cut the fabric that is going to fill the center. I didn't take pictures of this with the front, but you will do the front first as it's easier. Just pin your triangle of fabric and sew it down to the hem.
Step 6: Cut strips about 3" wide to make you bustle pieces. Each will be a different length as you are going to sew them onto this triangle, so I found it easier to make the strips of fabric super long and just cut whatever I needed off the end.
Step 7: Pin your ruffled strips to the triangle. Make sure that each strip covers the top of the piece it is overlapping.
Step 9: Now, I will give you this step, which I didn't do until the end, but you get to learn from my mistake. Take your skirt before you put your bustle piece on and do the hem around the entire skirt. This will allow your bustle to hang correctly.
Step 10: Pin your bustle piece to the back of your skirt. I worked from the front, so that I could make sure the seam was even and got the denim in a straight line.
Here is the view of your skirt from underneath.
Step 11: Trim away all the extra fabric.Now enjoy your skirt! The bottom part of my bustle would have sat better had I done the hem first, then added the bustle, but it's flirty and fun!
Hope you all have a great weekend!