It's one of those "understand the concept and objective, then work on what feels right for you" things. I'll see if I can explain it clearly, then you can work on how the timing works for you to get it.
Stand like you would for a standing throw. Extend your arm toward your target. That's where your elbow stops. Now, you need to work on what comes up to that to put you in the best position there and where to rotate your upper body so you don't lock your elbow at that point.
Blake had said something to me similar to this. You turn away from your target and hold the disc rather loosely. You could pull it right out of my hand. You turn 90 degrees so your right shoulder is facing the target. No arm pull, just guide the disc into around the center of your chest keeping the arm and grip loose. As your arm comes across and starts to go out towards the target (with the wrist bent in a little) you start to pivot your shoulders around. As the disc is going away from you (about a foot or so) you should feel the disc start to move. At that point, your grip should tighten a little automatically. That's when you clamp down and PULL. Your shoulders should come around at about the time you get to an almost full extension of your arm and then pull the elbow off it's line, but the disc should be gone by then. Your forearm continues to speed through the hit and into the finish.
It made an immediate difference in my throwing. Probably 25' of distance with less stress on my body. Discs also reacted quite differently. My 170g SOLS which was not turning over much turned fairly easily, not to a roller, but it really needs 20'+ unless I release it with hyzer.
Edit: If you watch the feldberg video, you can see him IN around his left hip area, then he's away from his body after that, but the elbow stops and it's elbow chop, tendon bounce and the last second grip and pull timing.