Will take less than a minute to get.
Grab any car but try to aim for one that has a fair amount of power (C class or higher) and preferably rear-wheel drive but even an all-wheel drive or front-wheel drive vehicle can work.
As shown this can be done right as soon as you leave the Horizon Festival. Simply accelerate and reverse in place a 10 times and it will unlock. If you are having trouble getting a burnout just hold down parking brake or brake/reverse,
, while accelerating,
, let go of
and it is almost guaranteed to give you a burnout.
Additionally you can try for a burnout in place by holding down
at the same time and slowly letting off of
to get the tires to spin but not move forward that much. When it says at the top of the screen 'Ultimate Burnout' stop and wait for the skill chain to break or be banked and attempt again as it is easier to earn more burnout skills after that.
Lastly you can simply spin and burnout in place and wait for the skill chain to bank before starting again. This doesn't work so well with all-wheel drive cars but works great with rear-wheel drive vehicles.