Level 2: Pikachu's Play Days >> Cobalt Coast
There's a pinata party going on at the shores. Venusaur is your host and Pikachu's trying to hit the pinata that Butterfree dangles. Guide Pikachu by telling it where it is. Pikachu understands you best if you're close to it. The words you'll want to say are left, right, farther left, and farther right. Tell it if it's going the wrong way and it will turn in a different direction, usually the opposite direction. Tell Pikachu there or swing when it's in the way of the pinata. You can also say over here when you, Pikachu, and the pinata are aligned the same way and Pikachu should come towards you. Saying the names of the Pokemon surrounding the Pinata should also help.
Don't forget that if you're close enough to the pinata and Pikachu breaks it that you collect the things in the pinata (like a real pinata party) and quickly stash them in the toolbox. The reward for breaking the pinata is a nice, white harmonica, which Pikachu plays to summon Lapras and take you and Pikachu to Cobalt Island.
When you return to the coast, you can sometimes whack the pinata again and receive a toy sword. Lapras is there to help you even more when you try to hit the pinata. Sometimes it isn't, but it should be there. When you get the chance, try to hit five out of five pinatas to win the pirate flag from Venusaur. This reward is permanent and will appear in your room between the wood shelf and the book shelf.