#1: Make sure 你 have 2 3DSs, it doesn't matter if they're both yours 或者 if you're doing this with someone else. Make sure one has the Pokemon 你 want to duplicate while the other has a Pokemon they won't mind getting rid of. Also make sure you're 老友记 或者 can trade in any way besides the Wonder Trade 或者 GTS.
#2: The 3DS with the crappy Pokemon starts the trade. 你 trade the crappy Pokemon with the one you're duplicating. Proceed trade normally until 你 both have the Pokemon.
#3: The screen now changes to a screen that says "Connecting, please wait...". The 3DS who now has the crappy Pokemon waits approximately 4 seconds, then turns off their 3DS. After a bit, on the other screen it will say there has been connecting problems. Make sure the screen is black and does not have an OK option, 或者 else it for sure did not work, but even if it does have a black screen, it still may not have worked.
#4: Repeat process until Pokemon is duplicate. Note the Pokemon that is not the one 你 are duplicating will be gone, so make sure it's crappy 或者 something. Also, remember that this is a long, hard process. But also remember that when it does work, 你 will be very happy!

So if 你 like this please leave a 评论 and tell me which awesome Pokemon 你 have been duplicating! Have fun doubling awesome Pokemon!

P.S. So far I have duplicated a Moltres and a Mesprit. Yes, a Mesprit. And awesomely French one.