Tiff did have an enormous crush on Katie - but she also had a strong sense of romance. She envisioned herself coming out to Katie on a picnic, or in the woods, or at the symphony, or something else like that - but not this way. Not after being abruptly awakened, with Katie looking insane and under the influence of an arcane curse. She was not going to go through with this.
Of course, all that did not go through her head as Tiff considered her options. She mostly just thought 'NO!'
There was a small voice in her head, whispering 'Yes.'
'NO!' roared Tiffany back, and the voice was overwhelmed. Then, she decided to choose Transform. There were too many ways that 'Dare' could go wrong.
"Transform.", she said.
Katie looked put out, but recovered quickly. "You will become a super-horny lesbian slut." she said.
"Fine. Transform or Dare." Tiff said, not pausing to take a breath. She could already feel the changes taking place, and needed to restore Tiffany.
"What?" Katie said, hesitantly. She was looking confused.
"Transform . . . or Dare . . ." Tiff struggled out. Her body was rapidly morphing into a super-slut, and her brain was fogging over at the same rate. It was getting hard to think. "Pick Transform!!!" she cried.
"Transform." Katie said dully, but with a gleam in her eye. Apparently she figured that doing what Tiffany asked would get her to sleep with her.
"Augh- ergh . . ." Tiffany moaned. 'Sex, sex, sex . . .transform . . . katie . . .'
Finally she shouted out: "You're not a lesbian!"
That was done, and her mind collapsed into the super-slut. In contrast, Katie was slowly stepping back, the gleam leaving her eyes. The transformation took longer to leave than to come, apparently. Nevertheless, Katie suddenly found herself uncomfortably pressed by the newly transformed Tiffany.