Disney Infinity

You must do this online. You need at least 2 people (split screen). Your main doesn't have to be the one on top, oddly; this popped for me when my alt was on top. Therefore, only the host gets this, and it pops when either player is on top.

Otherwise, it's just a case of picking each other up. Player 1 is picked up by player 2 (X), who is picked up by player 3, who is picked up by player 4.

Some characters can't be picked up. We had problems with Sully, maybe because he's XXXXL, so you may have to swap characters to get this to work.

it's an online achievement.

You can do this one with 2 players and 2 guests profiles. Note : you can only play with people in your friendlist.

the player 2 lift the player 1 with (X),
the player 3 lift the player 2,
and at last the player 4 lift the player 3.
enjoy the nice walking totem ^^

Only the player on the top get the achievement.

Rinse and repeat :)

For this achievement, you just need to play a 4-Player game and Stack all 4 characters together. Stacking is when someone picks up one character, then the next character picks up the 2 characters together etc.

You will only need yourself and a partner to do this achievement, but you will both need 2 controllers, 1 Portal each and 2 characters you can place onto the Portals. You should have 3 that comes with the game (Sully, Mr. Incredible & Jack Sparrow). It doesn't matter if you have 2 of the same and import them twice into the game as that will count.

You may likely have to send a Friend Request to each other on the console, however it might be possible that this can be avoided.

To avoid myself repeating the same instructions again and again, please read this solution for more information...

Solution for It's a Party In Disney Infinity

It is believed that this achievement is glitchy in which only the host may be able to get it, so feel free to try out the achievement with your boosting partner, if you are not the host. But if you don't get it, you know you will have to return to the Main Menu and host an Empty Toy Box yourself to get it.
Whoever is going for the achievement needs to be the one that doesn't pick-up any characters and stand on top of all the other 3 characters. The easiest method is to get the 2nd controller of that person to pick-up the Main Player (Player 1) with , then get your partner who is not going for the achievement to pick-up the 2 characters together with and finally let the lonesome character pick all 3 up with . You might have to put the heaviest character at the bottom first and the lightest character at the top if the stacking does not seem to work in the game.

Once you have got this achievement, you will successfully have both online achievements done for the game, with the remainder of the achievements obtainable with just yourself playing only. Hope all that helps, good luck.