There does not seem to be an "official" name for this method. "Carabiner Rappel" is perhaps the simplest name, but carries considerable ambiguity. I've often called it the "suicide rappel" because of the pain it causes to the collarbone area. Some people call it the "dinosaur ring" because of it’s quite old-fashioned, but that name also applies to other devices.

This method is supposed to be a less painful improvement on the body rappel (dulfer), but I can't agree. The rig provides little friction compared to almost everything else, so most of the heat is transferred to the shoulder, especially the collarbone area. In addition, I've found that the rope forces tend to cause me to double over.

Warning: Don't even think of trying this without a belay, and then only on a slope you can stand on.

To rig this rappel, put on a seat sling (the traditional diaper sling is dangerous enough), and slip a carabiner into the sling and the rope. Do not use a single non-locking carabiner: either use a locking carabiner, or better, two ovals with gates opposite. Pass the standing line through the carabiner, over the shoulder, and down the back into the opposite braking hand (i.e., right shoulder & left hand). Like the dulfer rappel, braking is done by bringing the braking hand forward.

If only one carabiner is used, the carabiner should be oriented horizontally with the gate toward the braking hand. I've photographed this with an oval carabiner so that the gate location is clear, but one should never use a single non-locking carabiner for this method because the rope will easily come out of the carabiner, reducing the friction to zero.

Given a choice between this and the body rappel, I will choose to not rappel as the first choice, the body rappel second, and this last.