Fighting Against Opponent's Underhook

Dealing with an opponent's underhook when passing to side control:

1. Recognize the moment when the opponent's chest faces the mat more than their back, indicating you're losing the ability to keep them flat.
2. Use the shoulder as a frame to prevent the opponent from turning into you and accessing your hips and legs.
3. Post your hand on the opponent's hip or thigh to slow their movement, and place your other hand behind their head to control their posture.
4. Before moving to the opposite side, circle slightly towards the opponent's head to avoid their hidden arm and gain a better position.
5. Replace the hand that's posting on the opponent with your foot and drop your elbow into the space created by their underhook.
6. If you catch their arm, use it to prevent them from turning away and secure an underhook on the far side for better control.
7. If the opponent's shoulder is still off the mat, use a kickstand motion with your toes to prevent them from getting their shoulder heavy on the floor.
8. Close the distance with a seatbelt grip and decide whether to take the back or transition based on the opponent's reactions.
9. Alternatively, you can go over the opponent's hip by weighting your armpit on their elbow and using their movement to position yourself for an attack.
10. Control the opponent's elbow with an internal rotation grip, similar to a heel hook, to limit their movement and set up for further attacks such as an omoplata or spiral arm lock.

These techniques provide solutions for maintaining control when the opponent has an underhook and is attempting to turn into you.