The pick-up point where a bridal gown is adjusted to keep its train from dragging on the floor — usually at the wedding reception — is known as the bustle.  The actual task of draping the gown is known as ‘bustling' the gown.

The bustle may be an “over bustle” which is buttoned or hooked under the bow at the waist, or a “French bustle” which is a combination of ribbon and loops tied together under the skirt.

Merriam-Webster Online Dictionary
bustle (verb)
intransitive verb
to move briskly and often ostentatiously
to be busily astir - teem
bustle (noun)
noisy, energetic, and often obtrusive activity - the hustle and bustle of the big city
bustle (noun)
a pad or framework expanding and supporting the fullness and drapery of the back of a woman's skirt or dress , also the drapery so supported
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