https://youtu.be/HMGHG1szm3Q
He starts talking about it at 4:35 or so and mentions it just after 5:00. I think what they mean is they vary the speed of each wheel in a turn to help the turn, but maybe there is more to it.
Here is what Wiki says about the concept
"Torque Vectoring in Electric Vehicles
In an electric vehicle all-wheel drive can be implemented with two independent electric motors, one for each axle. In this case the torque vectoring between the front and rear axles is just a matter of electronically controlling the power distribution between the two motors, which can be done on a millisecond scale.
Torque vectoring is even more effective if it is actuated through two electric motor drives located on the same axle, as this configuration can be used for shaping the vehicle understeer characteristic and improving the transient response of the vehicle,. In case of electric vehicles with four electric motor drives, the same total wheel torque and yaw moment can be generated through an infinite number of wheel torque distributions. Energy efficiency can be used as a criterion for allocating the torques among the individual wheels,.
In 2012, Mercedes introduced the SLS AMG Electric Drive. Mercedes engineers were able to make the system work with a higher traction torque level on the outer wheels than on the inner wheels during cornering, in order to tighten the turning radius."