You can try stuffing her hide with fleece strips. People use them for their hedgehogs, rats, hamsters, etc and are readily available in fun colors on Etsy. For my dragons dig box, I used millet seed. I bought an extra large water bowl and filled it partially with millet. My dragon never uses it and prefers to dig at his tile in his cave. You could try alfalfa pellets as well. There's also a really cool product called Excavators Clay by Zoo Med. It's a loose sand that you mix with water, then you shape it into anything you want like a burrow or cave, and then it dries hard. I feel this would be great for dragons as it isn't loose, so if they licked it they wouldn't be ingesting it, but it's like compact earth so they could still dig at and form their own little burrow. Once I upgrade my dragons tank his substrate will be tile and I'll make cave out the Excavator Clay s he can burrow away as he likes. Look up some videos of it on YouTube, it seems pretty neat and would make for a good dig-corner or something