Basically when someone puts you in a guillotine the defense is to stack and put all your weight on your shoulder into their throat and then sit on the opposite hip to escape your legs out into a side control position. If the opponent continues to hold the guillotine... (Which is kind of what he was doing)... Then you can trap the other arm with your legs (what osp did)... Control the cross arm from moving to create space (what osp did) and then keep applying downward shoulder pressure to make opponent tap.
Super glad for Osp... Takes a pretty bad grappler to get that choke though. Anyone blue belt or higher in Jiu Jitsu and you aren't going to land that