QQ

[Vold]

Straight copy/paste from wikis:

To recharge your whistle, trade it to a VCS member. You will have to pay 400gil for each refilled charge (a total of 10,000gil for all 25 charges).

• It appears that not just any VCS Member will do. With 0 charges, I tried trading to the boy in Bastok's chocobo stable and nothing happened. My chocobo was raised in Sandy.
• If you have dropped your whistle, you will be required to pay 20,000g to get a new one from your VCS trainer.

You can also trade a Whistle Coupon and an old chocobo whistle to a VCS Trainer to obtain a new whistle.

Congrats whoever wrote it, you didn't waste your time.