Someone's got your head on the ground. Classic bully position -- they're sitting beside you, cranking a headlock, and you're stuck. This is one of the most common self-defense scenarios you'll actually face, and the escape is simpler than you think.
First priority: don't get hit. Sullivan is clear on this. Keep one hand ready to block strikes. If he lets go of the headlock to start punching, you need that hand up. You can feed it to his bicep for control, or just use it as a shield. Either way, protect yourself first.
Now here's the technique. Take your far leg and hook it over his leg -- the one that's sticking up. This leg hook is VERY powerful. It puts immediate pressure on his headlock grip and makes it hard for him to hold on.
From that hook, you've got two paths. Either climb up on top of him and pull your head free, or pull him back on top of you and scoot underneath. Both work. Sullivan shows scooting underneath him, getting your other hook in, and suddenly you're in back mount. Yeah, that just happened -- you went from getting your head crushed to having his back.
Even if he's got both hands locked on the headlock, it's hard to maintain that grip once both hooks are in. Pull your head out, and you know what comes next. Rear naked choke.
The whole sequence flips the worst ground position in a street fight into the best one. That's the point.
For more self-defense escapes and choke techniques, check out our complete self-defense techniques guide. Get the full course in the How To Win A Street Fight bundle.