In a quick change of the fight, Sukuna took advantage by accumulating all his cursed energy in one of his fingers & forced Gojo to ingest it. Everyone got up including you when they saw what could be a new threat

Suddenly Gojo began to laugh exaggeratedly, wiping a small tear from his eye "Did you really think you could have control of my body? How naive" The voice changed to Sukuna's showing irritation "Tch, what a bother"

The fusion was complete. GoSu stood before them, a being of unparalleled, intellect & cunningness, the perfect amalgamation of Gojo’s boundless potential & exceptional tactical & adaptable intellect and Sukuna’s malevolent force & cunningness. The air crackled with cursed energy, and the very ground trembled in anticipation of GoSu’s next move.

GoSu: “So… (both Gojo’s & Sukuna’s voice) … it seems we’ve reached a compromise.” His smirk is just like Gojo’s iconic smirk with Sukuna’s iconic arrogance.

He quickly made numerous binding vows, many of which are unrevealed to his opponent. A very clever, cunning, 5D-chess, galaxy-brained being.

GoSu: “Heh, what do you know about binding vows? They can be quite useful” GoSu smirks, mischievously

[Due to his galaxy-brain (meme), GoSu likely has multiple incomprehensible, nonsensical, stupidly absurd, convoluted layers of these binding vows pre-prepped (like he’s Batman) for any situation. The more severe the limitation, the greater the power boost. The sheer unpredictability of his Binding Vows makes GoSu an overwhelming force. He’s like a 5000 IQ galaxy-brained GigaChad.]

GoSu: ”Checkmate noob” He mockingly said like Gojo. “I made a binding vow unto myself known as Galaxy-Brained. It goes beyond just being "smart", becoming an intellectual force of nature. I can instantly outsmart and outwit anyone in my path, always make the right decision while avoiding all errors & failures.”

He playfully smirks

[His ”Living Hax” (all haxes) binding vow is also in play.]

A Binding Vow (縛しばり, Shibari?) is a pact made with jujutsu that creates conditions for themselves or agreements with others.

Binding vows are considered by all jujutsu users to be one of the essential tenets of jujutsu sorcery. They are, in essence, contracts that an individual can form with themselves or with another person. By adhering to the rules and restrictions established in these contracts, a user can gain increased power or achieve a specific goal; however, breaking a binding vow has consequences.

Vows with Oneself

As a product of negative emotions, cursed energy responds to the desires of its individual user. As a result, the user can increase the power of their cursed energy by stating a self-imposed "Cursed Restriction" that creates riskier conditions to use their abilities. For example, by divulging one's cursed technique, it creates more risk for them, making their cursed energy swell in response to its user's resolve.

As a product of negative emotions, cursed energy responds to the desires of its individual user. As a result, the user can increase the power of their cursed energy by stating a self-imposed "Cursed Restriction" that creates riskier conditions to use their abilities. For example, by divulging one's cursed technique, it creates more risk for them, making their cursed energy swell in response to its user's resolve.

In addition, creating rules for using one's cursed energy and abiding by those rules which allow their cursed technique to improve in strength. The penalty of breaking a binding vow with oneself is the loss of whatever was gained through the contract.

Vows with Others

Contracts created between two or more individuals are bound by cursed energy. Both parties must agree to a particular set of conditions that benefit both parties. The penalty for breaking a Binding Vow with others is considered to be far greater than that of a self-imposed Binding Vow.