American Bustle

My best friend is gettinmg married and she has advised the bridesmaids that our dresses need to be alter with an American Bustle (the dress has a small train). The seamstress that advised her of this says there is only one way to do an American Bustle, but we are being told by some of the other seamstress that there is more than one way to do an American Bustle. Can someone advise what an American Bustle is or how it is to be done?