Cultural adjustment

I was inspired - if that's the word for it - by yet another thread in FAP Britpicking about underwear in the UK to ponder what the Hogwarts girls are really wearing. Popular as the theme may be in fanfic, I doubt very much that if Ginny took Hermione underwear shopping it would involve lacy bustiers. So here follows very short fic.
(  All items to be marked with the student's name )

ETA: Given the amusement, I shall confess that this is not in fact my sole magical underwear fic (perhaps I ought to be ashamed of that). The first can be found here in Fiction Alley Park.

Any more takers for the first lines meme before the answers are revealed?