in the video shown it is a very slim chance of catching anyone with that arm bar, if they have the slightest clue of how to grapple.i have never caught anyone that had 6 months of training in the armbar video
your more likely to catch people form attempted escape or bait with a lapel choke, from s-mount, or useing your guard to ladder, flying arm bar, stepping over if they turtle, side contol opposing arm.
don't get caught keep your elbows close to your body.
on your back, and they are trying to finish. palm away from his chest, i see many people try to defend armbars by holding thier hands from the start, you are better off the arm they attack put that elbow as tight to your body as possible, with your free hand place over your elbow of the arm they are attacking and help press arm close to body. this will buy you some time, the goal you have is to get his leg off your face, or sometime disrupting his allignment by putting his other leg in between your legs, and trapping is enought to break his leverage to get his other leg off your face, then you will belly out into his guard.
from in his guard, his goal is to make an angle use his legs to break your balance. there is acouple things you can do, when he tries to bring his leg over your face, palm away from his chest, catch the crook of his leg, this will not let him apply the pressure to your face to finish, i do this with bringing him up on his shoulder bladesas i brace him up with my leg and crunch down with my weight attempting to go chest to chest and stck him, i now twist my hand like i am turning a door knob pulling my elbow past his groin. or i will clasp my own hand if it is past the decribed point. when i do this i am fighting his pressure, i will spread my base and shifting to the opposing side of my locked arm and drop my base, pulling my elbows down, this motion lays him on his side so he does not have the floor backing him for a powerful armbar, his makes the fight his grip VS, his legs trying to extend my arm, my 2 arms pulling, it also puts him in bad possition because i already started my pass, and have killed his legs.
there are many more attacks and defences
"every second your not training, he is..... and he is doing it, just to kick your ass"