Our friend Professor Jean Jacques Machado has a feature in this months Jiu Jitsu Magazine specifically on how to attack the turtle position via a series of chokes. Two things I love about this article... one is the variety of chokes JJ offers, with variations I have not seen other places. And the other is the constant inspiration Jean Jacques Machado offers all of us where a man with virtually no fingers, nor a functioning hand, can specialize in a variety of collar chokes. He never let his birth defect EVER slow him down not hold him back. Respect.
Random rare Youtube find... I stand to be corrected but I believe this is a copy of the DVD that accompanied Rigan Machado's "The Triangle" book, coauthored by David Meyer, that has been long out of print. Regardless this is a 90 minute tutorial gold mine of information for martial artists of all backgrounds. Mastering the triangle choke will make you a more versatile martial artist. Here is pretty much every detail of how to get into and finish the triangle choke from every conceivable position: