Junior Racing Champion

You can mount have your friend mount your Sandstone Drake and just fly straight for about a minute. I used my second account for this and got the achievement with this method.

Find someone or use your second account, use [item=208825], and have them follow you until 30 stacks, then they use the toy, and you follow them until you have 30 stacks.

I don't know why every comment is full of useless information. Get to the point.

Just did this on EU with 1 other party member, this was the strategy.
Toy is from this year's Christmas Presents under the Ironforge and Orgrimmar Christmas Tree, near Greatfather Winter.
Overall takes less than 5mins. Cooldown is reduced to 8mins during Winterveil Event.

1 - 2x Players group up and go to the top of Valdrakken tower (Seat of the Aspects)
2 - Both mounted up on dragon-riding mounts (don't know if this is required)
3 - Player 1 uses the toy [item=208825] and Player 2 follows
- You can actually just run in circles around the Seat of the Aspects, and there is no need to fly or dragon ride
4 - Wait until Player 1 hits 30x Stacks of Course Tracer and Player 2 hits 30x Stacks of Course Racer
5 - Swap to Player 2 using the Junior Timekeeper's Racing Belt and Player 1 following for the same 30x Stack buff

Congrats! :)