Getting your back taken is the worst thing that can happen in Brazilian Jiu-Jitsu. It’s a position that’s most difficult to escape from; and a position from which your opponents have the highest percentage submission at their disposal… The Rear Naked Choke.
If you’re caught in one or getting close to being caught in one, you have two primary options for defense. Professor Tom, from The Grappling Academy, explains.
TWO DEFENSIVE OPTIONS FOR A REAR NAKED CHOKE DEFENSE
If the opponent is “fishing” for your neck but hasn’t gotten to it yet, your primary focus needs to be establishing a 2-on-1 grip on their choking arm. You’ll use this grip to keep their arm away from your neck and chin (which you need to keep low at all times). If they switch the choking arm, then you need to reestablish your grips on it – it really is that simple.
However, if the opponent has already established their Rear Naked Choke, then you’re in really deep trouble. In this case, there’s really not much that you can do other than fight the “top hand”; the one that is placed on the top of your head.
Namely, if the opponent places their top hand too high, you can reach back and peel it off. After peeling it off, you can go 2-on-1 yet again on the choking arm and neutralize it. But, if they hide their top hand with their chin (as they should)… You’ll have to tap out and learn more on preventing, rather than escaping, the Rear Naked Choke.