You can't hold it, you click "Use" in the mini menu, and it turns Shaymin into it's Sky form.
You cant make it work. You have to have the original shamin you got the Gracidia Flower from.
This is a rumor of how to get it.
A "Gracidia Flower" is what makes a Shaymin turn into its sky forme.
By taking shaymin to the flower shop in goldenrod city.
event
give it a gracidia flower.
I don't think any particular slot in your party, just go to Floaroma Town and talk to the lady next to the flower shop in order to obtain the Gracidia Flower. Hope this helps :)
the shaymin in your party has to be a legit shaymin. not only that, you only recieve the gracidia flower if you enetered the wifi event. otherwise simply trade the legit shaymin to heartgold or soulsilver, then with it at the front of your party you must go to the woman who gives you the squirtbottle in goldenrod city. she will give you the gracidia flower, but it can only be used during the day. i think 8 am to 5 pm.
AFTER you catch shaymin if you go to floaroma town and talk to the woman near the entrabce she will give you one.
Gracidia flower. I'm not sure how to get it though, sorry. hope this helps! .
She probly won't give it to you because you need to have shaymin in your party. Then she will give it to you.
It's actually really easy to get the gracidia flower in Pokemon SS&HG you just bring a legit event shaymin to the flower shop in Goldenrod City and one of ladies will give it to you for free. If you have a non-legit shaymin that's probably why you're asking this question. Find it from a website like Pokesav or Cheat code central or i bet they have it on Action Replay.com