SCARLET NEXUS

You can do this when getting into the second area of Abandoned Subway: Suoh Line 9 (at around Phase 2 I believe).

Things to note: I did this as YUITO, I’m pretty sure there is a different variance of enemies there as Kasane (thanks comment section). I’d recommend just playing as Yuito for this achievement and you can get this early on.

Edit: the Kasane guide is the last paragraph at the bottom of this guide.

Now for the YUITO guide ⬇️

When you get to the second area in there called “Inside Abandoned Line”, shortly after defeating the first set of enemies there, do not go along the train tracks on the left, there is a cave off to the right. As soon as you enter, 3 rummies will spawn, all with a crush bar shield.

What you want to do there is get them close together, and then pick up the metal pylons off the floor by holding LT, and then spinning the left stick around until you finish the animation for that object. If you were lucky, all 3 will now be stunned. Now you need to use Brain Crush (LT indicator on enemy) on the enemies. ALL 3 MUST BE IN YOUR LINE OF SIGHT ELSE IT WON’T WORK.

Got this after 2 attempts myself, so it shouldn’t take you long at all.

Edit: Now the Kasane guide ⬇️

Thanks Tostiee for the comment! This particular individual said that you can get this at Kunad Highway (in the second area with the buses). Simply jump onto one of the buses and drive it down towards a group of at least 3 rummies, do not run them over though. What you do instead is press LT just before you do run them over and Kasane should throw the bus at them. If you got lucky, all 3 should be stunned, now you simply have to get them all in your like of sight and press LT to do the brain crush finisher. Good luck!

In this video guide I will show you how to defeat 3 enemies at the same time with Brain Crush. The best special object to throw at enemies to instantly drain the crush bar is the pylons that are in a pile. This is also an LT ability. There are quite a bit in the beginning of the game.

Now the best possible spot I found is in the Abandoned Subway: Suoh Line 9, area Inside Abandoned Line. First thing you want to do is get rid of your teammates by going to the party tab and pressing RS on your allies. As you start, kill the enemies and head into the room to the right. There will be two piles of pylons, one to the left and one to the right. Choose a pile and start standing by it. One all three enemies are grouped up use LT to use your ability to manipulate the pylons and instantly get the crush bar drained. Now you will need to stand at a decent spot to view all three enemies. Not too close or you won't be able to see them all. Once you see all three and make sure the bars are gone, press LT to get all three and the achievement will pop.

At the beginning of Chapter 2 you’ll play a capture the flag game in Kikuchiba. After you pickup the “flag” you’ll go up to floor 2 of the Mid-level shopping district. You’ll get to an area where you can hold LT on these white, bent telephone poles. When the 3 enemies spawn in just hold down LT on the telephone pole and it should completely wreck all 3 enemies’ health to nothing. Then hit LT again to do the Brain Crush and your character will lift them all in the air and insta-kill them.

Finally I got the achievement. I spent hours just to get this. (because I tried to get this in the subway first)
Here's how I did:

Go to: --> Kikuchiba Sub-Level Underground Facility
Go all the way up. There's a long stairway and there's a save point here. I recommend to save here. After that go up almost immidiately 3 Buddy Rummy will spawn. There're metal objects on the ground you can use them with . Make sure before use they are close together (not too close), and in line. If you think its okay use . Spin a few time until health bar is almost empty. You can use if you think its okay, but not necessary.
If you killed one of them reload (there's no load option in game so you have to exit and load from main menu, unfortunately). If all alive and stunned, make sure they all line of sight. Just press .
I did it on Normal difficulty in Standby phase 2!

I did this on the first training mission: A01 Basic Training.
Set difficulty to Easy, and use the Y button attacks with Yuito to break the guard on the second group of enemies.
Slowing down time helps a bit if you're having trouble.

I did this on Level 80 with the best weapons equipped, but you can probably do this anytime you get access to the training missions via the TV.

I tried multiple times using the other guides but just couldn't do it because I always had an enemy out of position. However, I was in Phase 12:


When I noticed three Session Pound extremely close together. This is immediately following the Archivist. Make sure the following is turned off:

1. Auto-Lock on
2. Aim Assist
3. Aim Assist (Locked On)

Then activate Hypervelocity to make sure they don't explode in your face. Finally, knock their brain crush meter down, make sure you see all three and hit .

EDIT: I just found a spot with four Session Pounds during my second playthrough during Phase 12 on 4. Memories of Pursuit.