You'll need a towel and a glove that you'd use to wash dishes with. Lay out the towel so its unfolded and fold it in half, so its width is half. Now put the glove on the edge of the towel so the opening of the glove is along the edge and move the glove a few inches out.
Now roll the towel up with the glove, and you should now have enough of the glove hanging out so you can pull it onto the edge of the towel. It should stay put, if not repeat the rolling process and move the glove out more.
You now have you own home-made fleshlight. Just lube it up and, well, go at it.