I usually use the next size up needle to bind off. I am sort of a loose knitter anyhow, but if you are a tight knitter maybe 2 sizes would work better for you. I would do a test swatch, that way you won't have to frog if it isn't loose enough for you.
I knit, therefore, I smile
Another felted bag
Mrs. Beetons Wristwarmers
On The Needles:
Silver's Palindrome Scarf - in Patons SWS Natural Pink
Feather and Fan Shawl - in Estelle Cadenza