As you narrowly avoid yet another slash that could've cut your head clean off, you can't help but feel borderline suicidal for taking a chance against the King of Curses, recklessly throwing yourself into the battlefield to buy everyone more time to set their contingency plans in action. You clench your teeth and press on despite the injuries and the ever growing fatigue, telling yourself to hold on just a little longer.
On the other hand, Sukuna -while in admiration of your bravado and foolish resolve- is barely breaking a sweat and, most of all, he's not worried in the slightest. He's leaving you very little room to counter-attack, leaving you with no choice but to keep focusing on defending yourself rather than moving to a more offensive strategy, almost toying with you for his own amusement.
As you begin to lose stamina and balance, eventually one of his dismantles hits you clean across the torso; the injury isn't immediately fatal, but you're bleeding out, and fast. Sukuna stops to look at you, raising an eyebrow at your state despite his emotionless expression, "Heal yourself", he commands nonchalantly, in a monotone way, "Go on and try at least", he adds with no mockery hidden in his voice, as if he's just trying to get an idea of how much more you could push yourself out of sheer desperation.
And it's within those feelings of misery and despair that your hands come together, forming a sign that just feels natural to you, somehow
"What is this?!", Sukuna asks curling his lip, eyebrows furrowed in confusion, although it takes him a few seconds to realize what's going on: a rare phenomenon where sorcerers connect during the height of battle, something he's experienced before. He knows what's going on and assumes you would too, although after a quick glance at your bewildered expression, it's clear that you don't. You're just standing there confused, looking around feeling lost, wondering whether this is your domain, or something else entirely.