Very Carefully! #:-)
Seriously in front of the trench is some barbed wire that I made.

I used 'sheathing' wire from an old Television 'Cable' wire. It may be similar to old 'Coax' cables.
Slice it open and you have the core wire with some plastic sheathing, then some woven mesh wire that is human hair fine. I cut a bunch of that out then.
1. String one long strand in a 'third hand' tool holding both ends tight.
2. snip short 1/2 inch long pieces to use as bards.
3. I wrapped the short one around the long one and gave the two ends of the short wire a twist.
4. Small drop of CA
5. rinse repease - do it again, and again, and again.
6. wrap the long section around a big dowel.
You may be able to find similar wire inside old computer mouse cable.