Dress bustle??

It's probably a wrist loop, you would wrap it around your wrist to keep the train from dragging the ground. I've never seen a dress come with a wrist loop already attached, but I'm sure some do.

I bet if you called, David's Bridal could tell you!

Agree with this. Daughter's dress had a loop underneath the train. The point of that loop was to hook it over the hanger to help take some of the weight of the train/skirt off the straps and ribbon loops attached at the armpits when the dress was hanging on a hanger. (The consultant at the bridal salon told daughter to ALWAYS make sure that loop was on the hanger to prevent the dress straps from stretching as a result of bearing all the weight of the dress while it was stored prior to the wedding.) I guess daughter could, potentially, have used that loop under the train as a wrist loop, if she wanted to carry the weight of the train on her wrist at the reception. She did not, so she paid to have a bustle created through a series of buttons & loops for the over bustle for the tulle/lace layers and ribbons attached under the lining to create an under bustle for those layers.

When you attached the loop on your dress to the bottom button, does the underside of the train show when you attach it to the button? If so, it probably wasn't intended to be used to create a bustle (since the "under side" of the train is usually hidden when the dress is bustled). A quick consultation with a seamstress could probably help you determine what you're currently working with on your dress. Good luck!

My dress has this as well.