When I first opened this, I was a little weary because it was SO smooshed, but it plumped right up over the course of a few hours. The directions say to give it 48 hours, but I feel like it happened much faster. It feels like a cushiony memory foam, and is such a great size for my 3 y/o. It's big enough for her to move around on and lay sideways and things. It does tip back easily, so we have it in front of our couch to avoid that, but it's not a safety risk as the chair is so thick/soft and it's not high up.