The no arm d'arce is also shown by Brandon Quick in the fade to black videos, he calls it the "coma choke" I think. I have tried this a few times rolling and have been unsuccessful actually "choking" my opponent with it; I always end up with a neck crank and have to let up. I'm sure there is a correct choking angle, but I have yet to find it. Also to keep in mind it is a great way to keep your opponent at bay when in a bad spot such as side control. I have used this a couple of times to stop my opponents advance from sc and to actually escape b/c it is an uncomfortable position. It seems like you would be easily armbarred by sticking your arms up while in sc, but your inside arm is coming across your chest and under opponents neck. your other arm is beside his head, so he will have to step to the other side to start to work a traditional armlock.