I have directions for a fleece pouch that I got off of here...
The most comfy pouches are made from poly fleece. I love anti-pill
micro, but any good fleece will work -- or for that matter, any fleece
that you can buy at Joann's

Another option is 100% cotton material.
Not all knits will work, some are too stretchy. I used a cotton jersey
that worked beautifully.
Measuring:
To measure for your pouch get a tape measure. Starting at your waist on
one side measure up and over your shoulder and back down to meet the end
of the tape. The tape will fit you like a beauty contestant's sash --
this is how your pouch will lie on your body as well. Measure three
times to get an accurate number. (example: my measurement is about 45")
You'll want the tape to go between your breasts and fairly close to your
rib cage. If you're wearing a t-shirt it should go there naturally.
Cutting your fabric:
Add four or five inches to your measurement to get the length for
cutting your pouch. You must cut with the length of your fabric, not
with your width. The stretch will be all messed up if you do it
width-wise.
Now that you have the length, select your width. I would suggest 24-30
inches. 24 should be adequate and secure for most babies.
After cutting, fold you material in half, end to end. then fold it in
half side to side. Smooth out all the wrinkles and try to get it as even
as possible.
To cut your curve start at the outside edge (by this I mean the side
with the open edges, not the folds) Cut about 3-4 inches from the end
and curve up toward the end as you go. When you open your fabric you'll
have a length of fabric with curves cut at each end. When these curves
are sewn together they will form a seat for your child.
Sewing!!

If you have a serger it is perfect for this, just sew the two curves
together.
If you have a regular sewing machine, use the setting for knits and be
sure to use a poly thread. Do some backstitching at the start and sew
across the curve (with right sides of fabric together) leaving about 1/2
to 3/4" seam allowance. Backstitch at the end. I would do another row of
stitching about an 1/8 inch from the first for security.
If you'd like you can finish the edges along the length, easy with a
serger. If you are using a regular machine I suggest skipping this. Knit
fabrics will not unravel. If you find that your pouch is stretching
without the reinforment you can always add the hem later.
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