Everyone knows the standard way to get the basic cross choke from the mount, but many times you will put the first hand in and feel unstable because the opponent has good hip movement. If you feel that you can control him better with your arm around his neck, here is a sneaky way to get the same choke. You are mounted on your opponent with your hips pinned to his body and your heels tight against his butt and away from his hooks. You hug his head with your left thumb in his collar and keep your weight to the opposite side with your hand on the mat to help you stabilize your position.

Your right hand will then grab his blocking hand and pull it toward your waist. You will then drop your body over it to trap it long enough for you to get your right hand into the collar. You can't hold it forever, but you will be able to do it long enough for you to slide your hand deep into his collar.

Here you can see my hand slide into his collar.

Once your hand is in it is going to be REALLY difficult for him to avoid the choke. Even if he rolls you, you can still finish from the bottom.

Obviously, with the thumb in grip of your left hand, you just have to circle your elbow towards his head to sink the choke. If he keeps his head in a position that makes it difficult to get your arm to the other side for the choke, be patient. His attempts to escape will eventually provide you with the opportunity.