Hi, there is not really follow me function on the tello. I have seen on youtube people which puts tello above car and thanks to the sensors and the tello stabilization, it follows the car when it move. Is it what you mean ? I would surprised it works above the bike because of the smaller surface. If you try, tell us, i would be curious to know...
You could try too the face detection function from aTelloPilots app but i presume it is too slow...