Anyone besides me that finds spilling skin unattractive? Have you ever seen a tightly laced corset with the skin crawling out between the back laces? I hate that! and let me tell you, it is also damned uncomfortable! This is why I include a modesty panel for every corset that is designed not to fully close on my body.
You can either go the easy route and include a rectangle of fabric between the last two panels of your corset on one side. But the modesty panels always move and never stay in place when you need them! So my modesty panel take a little more work while making, but really help staying in place once they are done.
You will start with two rectangles of fabric - 1 from your outer fabric, 1 from your lining. Mine are about 18cm wide and the length of the corset.
I serge around three sides with both fabrics right side on right side and leave one side open to turn the modesty panel.
Now turn the modesty panel! Next, I add the boning. I cut 2 times 5mm wide spring steel to fit in the length minus 1.5cm Then I sew with the zipper foot close to the bone. Repeat for the other side:
Next, I cut two pieces of 5mm wide spring steel to fit the width between the bones:
I sew in the lower bone first, then I sew between the two longer bones along the width to create a pocket for the second bone. Put the bone in and sew it shut! I used a serger and folded the edge over by hand, but you could also fold it in and sew it shut by machine.
Now we have a boned rectangle. The space between the bones is necessary to make the modesty panel flexible, so it doesn't matter if your bones are a little to small!
Then I insert 4 grommets, so you can lace the modesty panel in.
And this is how I lace it up:
Tataaaa! You are done with your corset now!