What does twining with an Aniimo do?

You are not steering a pet from behind. Twining transforms you into the Aniimo, and you see the world from its perspective.

While you are twined, your own kit is gone. Standard mobility, attacks and skills are all replaced by the creature's movement, combos and abilities, and you drive those manually. So twining is not a buff you switch on and forget. It is a different character with a different moveset, and you play it as one.

That includes fighting. You can hold the form and fight as the Aniimo, using its combos rather than your own.

Twining outside combat

You do not need a fight to use it. Twining can be activated while exploring, and the movement options it opens up vary depending on which Aniimo is active. A creature's traversal abilities are yours for as long as you are twined with it.

The practical consequence is that the Aniimo you have out is a traversal choice as much as a combat one. Two players standing in front of the same piece of terrain will have different options depending on what they are carrying.

Not settled: Because the exploration and movement options change with the active Aniimo, there is no single twining traversal kit to learn. What the mechanic gives you is whatever that particular creature can do.