Brawlout

For this method you need 3 controllers (You + 2 guests). You need to select Paco with at least your controller and one guest, the other guest can be whomever you want. Now get near the other paco and third character. Hit on the guest Paco controller, which will begin the grab and spin move. Immediately after hitting Y and the animation beginning hit on your own controller, which will cause your Paco to steal the character thus netting you the achievement.

I have attached the video of me doing this for those who do better seeing it visually.

If you hold with paco, he will grab the enemy and do a spinning throw animation. The easiest way is in local with 3 controllers, set 2 pacos up next to the third player and have the second controller hold y, then your main account hold y right after, stealing the player from him.