Step 1: Get in your car, bring your 3DS with you. Drive somewhere.
Step 2: As you’re driving, go beside every car you see and drive at the same speed as that car for at least 5 seconds, then move on to the next car.
If you come across a Target or Best Buy, run inside, and sprint to the electronics center where a 3DS would be, then run back to your car, and get back on the road.
If you come across a Gamestop, run inside, stay for at least 5 seconds, run back to the car, then hit the road again.
Probably best to do it on the drive home from work.
Don’t actually try this, gas prices and all. XD