US army calls the dulfersitz, a term I had never seen before, a 'hasty rappel'.

The hasty rappel is fine on moderate slopes and short distances and on a doubled line, with its extra width, it isn't to bad. I've did it using a single 7/16" line on a free hanging rappel and the best that can be said was it beat falling. The US army used three-strand rope that tended to cause spinning if you hung free. Feeling like you are being sawed in half and spinning made for an interesting experience. For a very long time I had a slightly pinkish stripe that wound round my body that made it look like I was into S&M.

Fortified with some early youthful experience we took to protecting ourselves using spare socks for gloves and stuffing extra clothing into the crotch and shoulder areas to limit the rope burn. Worked well enough.

For serious rappels we would tie a Swiss seat out of the rope and use a simple non-locking carabiner as a belay device. When I got around civilian climbers I was duly informed that my technique was "suicidal". Then again I didn't spend hundreds of dollars on gear, carry anything but the rope, gloves and a carabiner, or take twenty minutes to set up a simple 70' decent.