There's an artist girl in Kiloude City, kinda near where Calem's standing. If you talk to her, she'll gripe about how she can't paint anything and needs to see a girl in a feminine outfit for inspiration. Apparently by feminine she means the pinkest, frilliest dress you can find. So buy one of those (pretty sure ou can get it at the shop in Lavarre or Anistar), put it on, and talk to her. She'll break out of her slump and thank you by giving you that Slurpuff dress.