When a fruit falls off or is knocked off of a tree or bush, leave it for a few days. It will become rotten. Take the rotten fruit and drop it in a pond or any water. After a few days, look in the water. Instead of the fruit, there will be a Joy Candy, which is the advanced version of Happy Candy. Joy Candy fills up your Pinata's happiness meter to full. Note: This might not always work. This was done with Gooseberries in a pond, and it does take time.