Girl in a "shasha"

We got a delivery a week or two ago and left the box out for Julia to play with. She just fits in it standing, so when she gets in it she looks a bit like a doll we just had shipped in. Whenever she starts playing with it, she starts saying "shasha" - the Portuguese word for box is "caixa". She plays in it so much, its starting to collapse from all of the wiggling. What are we going to do next for another "shasha"?