How do you rappel without a harness?

There is a technique called the Dülfersitz in Europe, where you run the rope down between your legs, round the back of your thigh and from there diagonally across your chest and over your shoulder. The arm belonging to the shoulder that the rope pass over is held behind your back with the hand grasping the rope, and the other hand grasps the rope in front of you. It feels a bit awkward, but as long as you're wearing reasonably thick clothes it's not too bad. There's enough friction to give a controlled descent too.