Le Puff-Puff Club

You can enter Le Puff-Puff Club after you have obtained the Ultimate Key. To actually reach to this club you will have to go North-West from Argonia and unlock the purple door West of the waterfall. Once in the girl in the back room will offer the "Hero" a Puff-Puff. To get a Puff-Puff for another character change your lead character from the Line-Up" option under the "Miscellaneous" menu tab.