Gracie Barra Bristol, (BJJ), Can Sönmez, Bristol, UK - 04/10/2012
To transition from side control to mount, start by killing the near arm. the first thing is to reverse engineer the escape. When you're underneath, one of the worst things that can happen is they control your near arm. Now that you're on top, that is therefore exactly what you want. Start by digging your knee in to get it into the armpit: Saulo suggests faking a choke to get them to raise their arm. You want to slip your knee right under their arm, bringing your knees in close to their head.
Another thing to try is switching your hips to get that elbow up, then switch back to trap it. However you trap it, getting the near elbow out of the way is key to this particular method of transitioning to mount. You've now got several methods for getting to the mount.
A very simple side control to mount option comes from what Xande calls the 'super-hold', where you have one arm under their head, the other arm under their far armpit. Drive your knee across their hip (this part often isn't easy, as they'll be blocking), then raise that far elbow up, to twist their body and open up more space. Once your knee gets to the mat, use it to slide their legs backwards, then 'fishtail' your own leg, slapping it to the mat.
The reason for that is to stop that snatching half guard. If you simply swung your leg over, that can work, but it's risky. First, you may find either their near or far leg gets in the way. Second, should you get past the near leg, they still might be able to snatch half guard. Finally, even if you are able to clear their legs completely, there is a simple escape they can do mid-swing. As you bring the leg over, they can turn towards you and bridge, coming up into full guard. Therefore I wouldn't recommend this option: sliding the knee through and fishtailing is much safer.
A slightly more complex option is using reverse scarf hold to go to mount. From tight side control, having killed the near arm, switch one arm to their far arm, putting the other hand to their near hip, then shift your hips right back towards their head as far as you can. Your elbow is either in their far armpit or wrapped underneath for control. This position means you're also blocking their view with your entire body. Lean into them, using your body weight to help maintain control.
That therefore stops them from seeing exactly what you're doing (note that when Saulo shows it on his DVD, he suggests you mess with them by slapping their legs, until you can pick your moment). When you've got up really high and are ready to go (at this point, they should almost be bridging to relieve the pressure), grab their knee to stop them snatching mount, then bring the leg across. Ideally, you'll crush this to the mat, squashing both their knees together.
If you're able to clamp their knees onto the near side, there is the possibility of inserting your foot behind their knees and switch through to mount. However, it generally isn't going to be easy to get them into that position, so I wouldn't rely on this, but still, if you can get it that's an easy route to mount.
Second, you can grab your own foot and pull it across, or just squeeze it past your own arm, depending on your flexibility. This is useful when you have limited space, but personally I find it feels a little awkward, in that you might tangle yourself up in your own limbs.
However, as before the safest option is to slide your knee across the belt line, then fishtail when that knee touches the mat. You can also grab their belt or cup their far hip to stop them shrimping midway through. I feel this is the best method, using steady pressure to get into place, rather than relying on explosive power, flexibility or luck.