This was a difficult shot!
There are several variables working in this shot.
She started by standing on his knees as he leaned back holding her legs with both of his hands.
She held the hem of the dress in each hand. Now the challenge was to time 3 different things (her, him, and the dress) she jumped up throwing the dress up as he fell back.
They both ended up on their butts on the floor. The dress did not look good on some of the tries and on some he was already on the floor before she reached her peak....and I had to guess when to snap.
Like I said it was difficult but worth it!