They do like to bury treats. They save them for later
I would let her have a small blanket of her own and maybe she will bury them under it, but don't be surprised when you find one somewhere else. She probably snaps because you are stealing her treat...LOL I would also consider a short basket for a toy box. I got a wicker one from Pottery Barn kids with a pink gingham fabric cover for Cerise. It's not too tall so she can reach all of her toys.