I'm learning that there are two things that you spend a lot of time thinking about if you are a white belt, or if you are rolling with a lot of white belts. Things that stop becoming as much of an issue as you roll with more experienced fighters.
The closed guard is one. As a white belt, I spent most of my time trying to figure out ways to unlock the hooks of the closed guard. This was largely because a lot of white belts don't want to open their guards because they feel like they'll just get passed. This leads to the Guard Lock of Death, where the guy just keeps his hooks locked around your back at all costs.
The other one for me has been the forearm across the throat. There's a place for this, I suppose. But the majority of the time that I've had to deal with it has been with white belts, often larger white belts who managed to get a dominant position like the mount.
Rodrigo showed me a nice, americana counter to that forearm--a counter I blanked out on last night during a sparring session. First, always look to the elbow. That's something I picked up from Matt Serra during an Ultimate Fighter episode. Second, secure the elbow and the wrist. You might be able to upa out of it if you've been mounted--but remember to trap the leg on that side, also.
Whether or not you upa first, the next move should happen pretty quickly. Slide the hand that was securing the elbow over his forearm and then under his wrist to grip your wrist in the americana position.
Throw the americana to the outside sharply, keeping the right angle of the bent arm intact. Be ready to ease off because if the guy doesn't roll over to take the pressure off, then the submission will be immediate. Rodrigo caught me with this move so quickly I didn't even realize what had happened.
