This is a great way to bag squirrels, and if you have 35/1000 safety wire in your pack (like you should), it is easy to make.
Find a branch, about 6 or 7 feet long. Make a series of small snares just large enough for a squirrels head to pass through and tie them to the branch. Be sure to tie on alot, and be sure to place the knots on the underside of the branch. You will want the snares to be placed all around the pole to ensure the squirrel will pass through them. The reason you want to put the knot on the bottom of the pole is so the squirrel tires and fall off the pole to hang, rather than allowing it to sit and chew through the wire. Now lean the branch against a tree that squirrels frequent, like a tree with a nest or several nests.
You should have squirrels within 24 hours with the correct placement.