Extract yourself from the Guillotine Choke while locked inside the guard (opponent's legs wrapped around your waist, his arm around your neck).
First, place your own arm around your opponent's neck to alleviate pressure.
Now, drive your legs into the ground to force your opponent backwards and into a pressured position.
Tuck your chin in, towards your opponents ribs.
Bring feet and legs together (rather than splaying them apart) so that the opponents leg-lock can be forced down around your waist and around your own legs.
Now, fall to the side so that opponent is no longer on his back, pushing his outward leg out of the lock position.
Bring your own legs around so that you are perpendicular to your opponent's body, setting yourself up in a strong, side-control position.