Gracie Barra Bristol, (BJJ), Can Sönmez, Bristol, UK - 01/10/2013
Start off by immediately bringing your knee up on the choking arm side. Angle it inwards, to prevent them from rolling you back the other way. In one quick motion, move your head forwards and simultaneously shove their head sideways (this is presuming they know what they are doing and have their head tight to yours for control). Look towards them, keeping your head and neck firm in order to stop them moving their head back into place.
Push off your leg and bridge back, aiming to get your shoulders and spine to the mat. If you aren't able to get your head past theirs, still push off your leg. Put your head on the mat and then grind it underneath their head. This isn't pleasant for either of you, but it is generally effective: preferably you can get your head past theirs in the gentler method above. If you can, clamp your arm that is nearest the mat to your side, aiming to trap their arm. To really immobile them, see if you can use that same arm to grab their opposite sleeve, meaning you're using one arm to control both of theirs.
Due to your body slipping off to the side, they are probably going to try and come on top. To do that, they need to be able to turn their legs down and then away from you. Keep your legs in tight to block them: with your leg back, that forms an effective barrier to their efforts to turn. There are a couple of ways you can do that. The first one is hooking their top leg (if they're trying to turn on top, they'll be on their side) with your near leg. Get your foot towards your bum to lock their leg in place. Alternatively, step your near leg behind the knee of their bottom leg and pinch your own knees together.
With your near arm, grab their trousers by their top leg (either by the knee or a bit lower). When you have the opportunity, switch to grip with the other hand, which means you can bring your near elbow down past their body, on the inside. At this point, make sure you've got your outside knee angled towards them, once again for base. Shrimp away, get your near arm back, then turn straight into the leg squash pass position.
As in the simpler version, I prefer to get control of the shoulder and head. Instead of getting my elbow to the floor and turning like Dónal, I like to either reach across their neck and grab the gi, or better, reach under their head, grip the far armpit then lock my shoulder into their head and shoulder. Either way, push off your free leg and turn to try and come on top. With your grip on the knee, stiff-arm so they can't lock their half-guard (if they do lock their half guard, this puts you in the opposite side half guard pass position, so proceed from there). Free your leg (pushing on their leg if you need to) and move into side control.
You're attempting the escape as above, but they have managed to get their heel to your hip and you can't prevent them moving towards mount. Instead, shove their lower leg between yours, then reach underneath their bum with your near arm, reaching up and shoving their far butt cheek. That should knock them forward while simultaneously dragging you underneath.
Wrap around the outside of their leg with your bum-shoving arm, just below the knee. Hide your other arm underneath their leg, or at least tuck the elbow in tight: if their sleeve is in reach, grab it. The first thing they will try to do when you put them in deep half is underhook that hidden arm, meaning you want to take away any space for them to wedge in their arm. From there, pull their knee outwards and spin in that direction, in order to come on top and pass.
Teaching Notes: I need to streamline how I teach the first technique, as I'm over-complicating it. I cut out the detail on hooking the leg, as I can leave that to the second technique: I can probably also leave out going through multiple variations of how to protect your neck. It's possible I could continue to split the techniques like in the past, spending a lesson on each, but combining them makes sense. Whenever I've taught the first technique on its own, I've invariably seen lots of people move from the back to mount during sparring and progressive resistance.
I'm also still not as confident as I'd like with escaping the back myself. I can generally get free, but then I'm rolling with people relatively close to my size but with less experience, so that's not a true test. My back escapes continue to feel sloppy and require too much energy. On the other hand, I am getting better at remembering to stiff-arm that leg, rather than getting so defensive that I trap myself in place (but only getting better, I haven't overcome the impulse yet).
Attacking the back I wasn't doing a whole lot, though it was fun to play with switching sides on armbars (because I'd been watching a video on that in Black Belt Requirements, which I'm hoping to have finished reviewing this weekend). I also cramped up a few times, so need to remember to warm up properly before I jump into sparring.