Step on the attack side hip to lock the guard passer's shoulder, and pivot. Use your elbow grip/free hand to lower the passer's head if necessary to help get your leg over to finish the armbar.
The triangle was a special of Coach Brock, a triangle from double wrist control. It took a little while for me to figure this one out, the step on the hip, pancaking your legs and then using that off leg to move the guy's arm out of the way and loop the leg around. Zee added a nice detail of switching to a two-on-one once you peel off with the second leg to maximize your ability to isolate the arm and head.
A good class and a really nice time of the day to train in a lot of ways. I didn't train at the midday session, and a part of me wishes that I did. Even though I was planning to train on Saturday, it felt weird not getting that midday session in. I don't know if I'll train next Saturday or not, but I'll definitely be looking to double up next Friday.