2 Part Technique - If you arrive at the Front Headlock, you should always be able to advance your position from there; whether it be to the Seatbelt, the Guillotine, or even a pass. If you feel him try to sit out to recover his guard before you can move to one of these options, circle around avoiding his legs while still holding on to the headlock, and hide your leg by kneeling onto his stomach for Knee-On-Belly. This can be down to both the left and right sides, and once you've established the Knee-On-Belly, release your grip, and reconnect with his arm out for the Guillotine.