As an addition to my triangle bean bag post I thought I’d write a quick tutorial on how I did my circle bag. Since I’m pretty new to sewing and was making an attempt to figure a few things out on my own I have no doubt that some people may have different ways of doing some things, but this is what worked for me this time around.
The overall construction is pretty similar to that of my triangle bag so I won’t get into that here. I started by tracing a circle onto the back of my fabric using a pencil and a lid to a container. (I’ve found there is no shortage of circular items of all sizes sitting around the house available to be traced.) For the inner bag just pin the pieces of fabric together and sew along this line, leaving a space open for turning.
The outer bag took a little more work. I chose 4 different types of ribbon and cut them to be longer than I thought I would want in the finished project (they can be trimmed down at the end). There was one ribbon that I chose to double over and make a loop with and that one had to be cut with the final length in mind. I pinned all the ribbon pieces to the right side of one piece of fabric along the circle. (Since the circle was stenciled on the back of the fabric this took a lot of flipping to get it exactly how I wanted it.)
Front view after pinning ribbons.
Back view after pinning ribbons
Once the ribbons were in place I pinned my two pieces of fabric together, right sides together, and sewed them together. Don’t forget to leave that ever important spot open for turning! I put my pins into the ribbons perpendicular to the way I’d be sewing because I had heard somewhere that if you do that you can leave them in while sewing. Although it worked out in this case I’m not sure if it’s a good idea with as tight a stitch as I was using. I heard the sewing machine needle hit the pins a few times which scared me, but no damage seems to have been done.
After both pieces are sewn, go ahead and trim the edges off, leaving at least a 1/4 inch seam. I then snipped my seam allowance to keep the bag smooth after turning. I probably ended up cutting every 1/4 to 1/2 inch the whole way around, but my guess is that was overkill. Just be VERY careful not to actually cut through the seam!
When you turn your bags right side out you should have something that looks a little like this. 
At this point just put the liner inside your outer bag, put in your chosen filler, and seam up the sides. (If you’re not quite sure how to do this, just refer to my triangle bag post.) All that’s left is to trim down your ribbons to your desired lengths. Also, to keep the ribbon from unraveling you can run a flame from a lighter across the cut, exposed end.
And there it is, a complete tutorial on how I made my circle sensory bean bag. I had a lot of fun coming up the idea and making them, and so far my son has really enjoyed playing with them.