Some questions about the tail spin feat

[Hammerspace]

I made a level 6 tailed goblin ruffian rogue with the level 5 racial tail spin feat and the level 4 rogue feat the harder they fall.
tail spin
"You excel at using your tail as a weapon to upend your foes. Attempt a single Athletics check to Trip up to two adjacent creatures. If you roll a success against a target, you get a critical success against that target instead."
the harder they fall
"You make your foes fall painfully when you trip them. When you successfully Trip a flat-footed foe, your target takes 1d6 bludgeoning damage. On a critical success, the target takes 1d6 bludgeoning damage plus your sneak attack damage."

I have 2 questions about the tail spin feat.

1.how does using it count for multiple attack penalties if I try to trip 2 enemies with it?

2.Does it combine with the harder they fall level 4 rogue feat the way I think it does?
If I use tail spin against a flat footed enemy and I succeed, that success is turned into a crit and I do 1d6 bludgeoning damage +sneak damage.

[Cordell Kintner]

It's only one roll so I would say it's one level up on MAP. And yes, it applies sneak attack. You tripped them, and it was a crit so you do what the feat says.

[Hammerspace]

another question, can you trip a prone creature?

[Cordell Kintner]

You can't, but they're (usually) flat footed when prone and you can deal sneak attack damage normally.

[Gabor Almasi]

"Attempt a single Athletics check to Trip up to two adjacent creatures" - the creatures need to be adjacent to you only or to each other as well?

Also, in case you are enlarged (i.e. have reach 10 feet) can you use tail spin against creatures within 10 feet or only the ones within 5 feet to you?

[breithauptclan]

Actually, this is a pretty valid use of thread necromancy. Congratulations on being a Hallowed Necromancer.

Gabor Almasi wrote:

"Attempt a single Athletics check to Trip up to two adjacent creatures" - the creatures need to be adjacent to you only or to each other as well?

It is a bit vague in the wording, but I would run it with that they just need to be adjacent to you.

There are other actions, such as Swipe that are more clear that the targets need to be adjacent to each other. Impaling Finisher also has a lot more strict requirements for positioning.

Since Tail Spin just says that the creatures need to be adjacent, I think it means that they need to be adjacent to you.

Gabor Almasi wrote:

Also, in case you are enlarged (i.e. have reach 10 feet) can you use tail spin against creatures within 10 feet or only the ones within 5 feet to you?

This actually came up in a different thread too. Adjacent isn't actually defined. The closest that I have found is in the

Reach trait that equates adjacent to 5 feet.

The standard meaning of adjacent is 'directly next to or touching', so I would rule that even if you have a natural reach with your tail, Tail Spin only works on adjacent (5 foot distance) creatures.