You have them in your Guard. They foolishly try to choke you, and when they do, you spin and catch their arm to do an armbar. But, they pulled their arm out just as you attempt the submission. When they do, you pull down on their arm or shoulder to keep them in close for a moment, and get your leg that was around their neck, to then go over their shoulder - and you lock your ankles together. This is the Triangle Setup position. And from here, it is all the same steps that we covered in the Triangle Choke.
Follow me for more Martial Arts Instruction on social media:
Twitter - @AustinKungFu
Instagram - @AustinKungFuAcademy
Facebook - Facebook.com/AustinKungFuAcademy