Marcio Feitosa of Gracie Barra shows the brabo choke. There is a gi version, but his explanation of that is still too confusing. The no-gi version is much more straightforward to me.
The brabo is a nice finishing move after you've rolled using the counter to the bear hug guard pass. As soon as you roll over into the side position, push down on the head and reach under with the inside arm to start the brabo.
The coup de gras is to pull upward with the inside shoulder, using your outside shoulder and arm to keep you in place.