I learnt how to twist down this year (at the age of 21) so I'm sure she'll pick it back up in no time. The things I do when I twist:
1) stick my hips forward & keep my whole boady tight before the bases pop to cradle the half or full (might just be my thing so I remember to twist).
2) Don't twist off the bases hands, wait until they have popped you before you twist.
3)whip your arms down to the side your spinning really fast.
4) Look it the direction you are twising.
That's how I do it and it works for me, but maybe a coach would coach it differently.....
I aslo practiced twisting on my bed at home. I'd put a shirt on the bed and twist onto it as I had a real bad problem with twisting over my base, so this made me make sure I was spinning on the spot and kept tight.
p.s I only know how to twist down from 2 legs, not from stretches, but I assume a simmilar theory would apply. :)