He bans that use of Semblances for the contest, which has a bit more time.

"Now now Emerald, no using Semblances to sabotage your opponent," Jaune chided Emerald. "The point of the contest was to turn me on more after all, it'd defeat the purpose if you straight up sabotage each other. If you want to enhance your own performances on the other hand..."

Emerald pouted as Neo glared at her, wondering what Emerald was using her Semblance to make her look like. She then grinned and snapped her fingers, creating two copies of herself that were making out. Jaune blinked. "Wait, does Neo have an illusion Semblance too?" he asked, pausing the contest for a moment.

"Yeah, though hers is a bit different," Emerald explained for Neo. "While I can pick and choose who sees mine, and strain my Aura if I want to affect multiple targets, hers has the advantage of being seen by everyone, though she can't pick and choose who she fools with it, everyone sees them. And if you make contact with them, they dispel. So yeah, we have similar Semblances, but with different limits and utilities."

As Neo nodded in confirmation, Jaune nodded. "Okay, that makes sense..." So on the surface, it looked like Neo had the superior Semblance, but really, Emerald's ability to pick a target to fool had its own advantages. For example, in this particular situation, since she could see what Neo was doing, whether Neo wanted her to or not, she could see what she has to outdo. By only using her own Semblance on Jaune however, she could keep Neo from getting any ideas from her.

And considering that now Jaune was seeing an illusion of Yang and Pyrrha 69ing each other, and another illusion of Ruby was fucking Blake on the bed with a strap on on the bed, while Emerald herself jiggled her own tits while tilting her hips, Neo could use those ideas.