Fortunately, it's quite easy to make a soft, conductive writing tool using some pretty basic materials. All you need is a pencil, an anti-static sock, and some patience to cut and sew it all together.
Step 1: Gather the materials
1. A pencil or pen (the non-pointy side is the side you'll be drawing with on your touchscreen).
2. An anti-static sock (such as this one, with X-Static in the foot area which contains conductive silver thread).
3. Scissors to cut the sock.
4. Needle and thread to stitch it together.
Step 2: Cutting the sock
Step 3: Stitch it up
Next, (see second picture) cut the rectangular section of anti-static sock material to be slightly shorter than the pencil's length. Then stretch the sock to so that it cover the pencil's entire length and hook it on the pencil's tip (this makes sewing it easier since the material is stretchy).
Finally (see third picture) sew up the rest of the sock alongside the pencil, leaving a gap between the two sewn sections so you can easily take the pencil out.