North South Choke as shown by ADCC/BJJ champ

https://www.youtube.com/watch?v=DcQtNN8jK10

So you passed guard and secured side mount position. The guy has perfect arm defense and he won’t give you his back. Worse, leg locks are not allowed! What can you do in this situation? I originally learnt “north-south choke” from Tito Ortiz who submitted Rumina Sato with it at ADCC 2000. This is the newest version explained in full details by Jiu-Jitsu world champ, Mark Garcia.