I wanted to create a custom bean bag for my baby and 3 year old for our holiday house. I found this pattern and tutorial from Straight Grain (see also fabric toy barrel post) very helpful and easy to use. I made 2 (one toddler and one baby one) in one day. I used a durable bull denim that I found at a local fabric store.
Bellow find the links to the pattern and tutorial.
Here is little Demetri sleeping in his custom bean bag. It was such a lifesaver to have the beanbag during summer at our beach house with a baby, and the bigger kids love to sit on them while watching tv or reading.
PLEASE TAKE CARE WHEN USING THIS BEAN BAG WITH BABIES. DO NOT USE THE BEANBAG ON TOP OF TABLES CHAIRS OR RAISED SURFACES. THESE BEANBAGS ARE BEST USED WHEN BABIES ARE NOT MOBILE AND WHEN THEY ARE STABLE TODDLERS.