The first time he used the Chimera Technique, Hyuga Ritsu had needed to get himself into the right condition, form Hand Seals to channel his Chakra, and perform the technique with painstaking care. In short, he'd been on edge, treading as carefully as if on thin ice.
But—
Things were different now.
After successfully using the Chimera Technique, he'd gained a deeper understanding of the Forbidden Jutsu. At the same time, his Body Regeneration ability had grown even stronger. All of this meant he no longer had to be so cautious when using the technique in the middle of a fight. He could skip forming Hand Seals to guide his Chakra, and he no longer needed to ensure his body was in peak condition.
Of course, those were only part of what gave Hyuga Ritsu the confidence to use the Chimera Technique in the thick of battle.
Another important reason was that when he'd pierced the White Zetsu's body with the power of his Shikotsumyaku, his body had sent a distinct signal of longing to his brain.
His body craved White Zetsu!
The hunger was intense, and it came with a powerful confidence that he could quickly "eat" the White Zetsu.
Hyuga Ritsu didn't fully trust the signals his body was sending him.
He still took two seconds to think it over, recalling how all sorts of powerful people in the future would show off by using White Zetsu's body in various ways. Uchiha Madara had even cut off a White Zetsu's arm right there and attached it to himself, and it worked without so much as a drop of superglue. White Zetsu's body, like the Uchiha's Sharingan, clearly had a plug-and-play quality.
After weighing all these factors,
Hyuga Ritsu immediately used the Chimera Technique on the White Zetsu in