Use the Note a bit, and add a "Faunus" trigger.

"Alright Yang, whenever I say, the name of an animal, followed by "Faunus Girl," for instance, "Cow Faunus Girl," you will gain sexy personality traits of, but not act completely like said animal. Nod if you understand." Yang nodded. "When I tell you, "Return to Normal," you will be yourself again. And by yourself, I mean your happy trigger **** self default mode."

Jaune then smiled and took the Note. "Whenever Jaune Arc uses the Faunus Girl trigger on Yang, her body will change to be like that Faunus. However, she will gain all the traits of that Faunus, not just one, provided Jaune finds it sexy. For example, if he says, "Cat Faunus Girl to her, she will gain the ability to purr, the ears, and the tail. Furthermore, if she gains animal ears, it will be her human ears turning into said ears, instead of simply having both sets. Also, if he says, "Cow Faunus Girl," she will lactate a sweet milk for the duration. When he uses the Return to Normal trigger, her body will revert to full human along with her mind."

He closed the Note and snapped Yang awake. She blinked and looked at him. "Oh, you're kinky," she smiled, having full awareness of his trigger after waking due to his programming. "Kinda feels like I wasted this outfit though..." Indeed, if he could turn her into a fox girl at any time, it kind of made her costume redundant.

"It did give me the idea, so not a total waste," he smirked. "Now get naked."

"You got it boss man," she replied, and quickly removed the fox girl outfit.

Once she stood naked, he considered what animal girl to make her for this particular round. Cow or cat girl was fun, but given her costume, might honor the spirit of her seduction effort to go with fox.