This Armbar Setup is so simple yet so effective. The reason being is it’s unexpected and is so easy to do you are just relying on the person reaching past your center line than attacking.
Having longer limbs I am able to create a ton of momentum with my legs. You can still do this if you are shorter but it’s just easier with long legs.
I started going under the legs all the time to finish because when I set the Armbar up like this I would almost stack the person on top of Me or I was in a position where I was already being stack like the can opener. Than I would have to figure out how to get out from under my opponent.
So what I would start doing is going under and mixing it with the Armbar sweep where you hook the leg and kick down towards the floor. One of them will work and I stay on the arm until it does.