I had some recycled polyester fleece leftover and was still in a creative mood.
I needed a sling to help me socialize the kittens. One which allowed me to use both hands to work while they slept, yet kept them close enough to my chest so they could hear my breathing and heart beat.

This design keeps the kitten directed towards your chest, where they can see and hear you.
Most baby or ferret slings point away from you, or have too much material between the kitten and your chest.

I tried to keep the instructions as minimal as possible.
This can be adapted to use a beach towel with safety pins, I needed a permanent one.

Step 1: 'Cut' Fabric

I used a recycled poly fleece stadium blanket
(there are always a ton donated to the thrift stores...and they are all from banks or software companies go figure)

I used the 50" width as I found it comfortable to wear.
however you may want it longer and cut it length wise.

cut to 26" width, for neatness I hemmed the cut edge with a zig zag stitch though fleece is not prone to unraveling. the Cut edge would normally just curl up, which is fine too.

Step 2: Fold Fabric

Fold lengthwise.
Bring the bottom UP about 8 inches
and the top down about 4-6, make sure they overlap at least an inch.

Step 3: Sew Ends

Sew each end closed (i used a zig zag)
What you want to create is a long pocket, somewhat resembling an enchilada.
with this fold and the secured ends, you have the most room without any escape hatches.

Step 4: Pin Ends Together

I just used safety pins to secure both ends together.
Makes it easier to wash.
You can always attach webbing and buckles for adjustability.

Step 5: Insert Kitten(s)

This kind of sling is very handy for socializing feral kittens.
or nursing bottle babies.
it allows you one hand free when you want it and two hands free when you can.
it also keeps the kitten directed towards your chest, where they can see and hear you.