Artemis BJJ (MYGYM Bristol), Can Sönmez, Bristol, UK - 11/03/2016
To transition from side control to knee-on-belly, you first need to have enough space. If you want to clear their near elbow, u7e your knee (the leg furthest from their head), then switch your hips back to trap their arm. Grab the collar behind their head with one hand, with the other be pressed into their far hip, both hands attempting to push firmly towards the floor.
Even if you can't clear their elbow, you can still transition to knee-on-chest. Bring the knee nearest their face right up to their head. Grip their collar and hip as before, and again push up and bring your knee to their chest. Though they have an elbow in the way, you will simply shove past it, bringing your knee outwards in a small arc as you do so.
From there, push off with your arms and pop your knee onto their chest (or belly, depending on their defence). The knee should ideally be pointing towards their far shoulder, keeping your toes off the floor to maximise the amount of weight on your partner. Your other leg should be out at a 45 degree angle, making sure that it isn't easy for them to grab it. Be sure to also keep that leg bent, as otherwise you're liable to lose balance when they move.
Keep your hips as low as possible, meaning you end up sitting on them, but with your bum off to the side of their body. You're going to use the arm that is gripping their collar to do a variation on the cross-face. Keep that arm stiff, pressing into their face. That should make it difficult for them to turn their head.
A simple attack from there is an armbar from knee-on-belly. Having got your knee in place, the natural reaction of your partner is often to push on that knee with their hand. It's painful, so shoving with the hand is the immediate response to get rid of all that pressure. However, this also frequently means that there will now be a gap by their elbow.
You can take advantage of this by feeding your hand through (on the inside). Wrap your hand around their tricep and pull in tight with your arm. That should now mean you can squash their arm against your shoulder. Also bring your head next to their arm, for extra control. Put your hand by their head, then step your leg over their head.
Having trapped their arm, you can now spin all the way to the other side to go for an armbar. Many people make the mistake of not spinning far enough, so lose the armbar. To prevent that, grab their trouser leg to help pull yourself round: you want to be facing the opposite wall, making a complete spin. Finally, drop back and go for the armbar, squeezing your knees together.
Teaching Notes: This is a simple technique, though personally I pretty much never go to knee on belly. Things to emphasise would be reaching right through and gripping the tricep, staying tight with your head and going slowly on the spin until you get used to the mechanics and knee entry. Getting that knee in the right place is possibly the hardest part, especially doing it smoothly. Next time, I should also mention the trouser leg grab, I forgot to mention that. Handy tip from Nic G, IIRC. :)
I think this will work well as a combination of maintaining knee on belly and the armbar, they seem to fit together. So, next time I'll do it as a combination class, with a load of drills for knee on belly (press up into KoB from mount, side to side, then into the armbar. Maybe an escape drill too?)