I just made this for my little darling when shopping.
It fits into this pouch, which is sewn on and folds under the cover when it is on the cart. It looks like a pillow:
And here is my sweet 4 year old daughter Maranatha showing us how comfy it is, lol!
I used this pattern, but didn’t follow the directions at all, lol! They were to time consuming, so I did my own thing. If I make one again, I am going to use pre-quilted fabric because the most time consuming part of the whole thing was quilting the fabric, and I didn’t even do a good job on it. So if you make one, buy pre-quilted fabric. Oh and buy bias tape, don’t make it, unless you have LOTS of time to spare, lol.