Daisy does this too! She's now 9 months and does it atleast once a day. It
has gotten a lot better though [from when we first got her @ 3 mos]
She used to chew the corners of the cushions of my
very expensive sofa (I had it before her) until I got a slipcover-the best purchase yet- and threw it over the sofa.
Now, she'll chew on the corners of the decorative pillow thats laying around if we're not looking. I hope she'll grow out of this stage as I'm told she will.