Could you describe it using thumb up/thumb down instead of palm? I am having a hard time following.
So let's say you have to settle for the arm-in Guillotine with their head under your right armpit. Your right arm is choking. At your laptop screen right now, gable grip your hands with your left palm facing your face and your right palm facing away from you. Now, lift your right elbow so that your thumb is pointing to the right, and now gable grip your hands again. The pinky side of your forearm should be choking them instead of the thumb side of your forearm. It's basically choking them with the outside of the forearm instead of the inside. it feels odd at first, but you get used to it.
I really hope I explained that okay. I'll try to find a video somewhere.