Why not?

You shrug and accept. She promised nobody else would be around, so why not? It could be fun, and pass the time until you're able to return home.

"Awesome! Let's play the classic Truth or Dare. I know that's more fun with like, four or more people, but this'll be a nice relaxing version. But I'm making the rules." She says it all so quickly you swear she's thought about this before, but you nod. She shifts eagerly in her seat, turning a bit to face more towards you, crossing one leg over the other.

It's been some time, so here's a refresher course! Alison stands at about the same height as you, but has long blonde hair. Today, she wears a pair of denim short shorts, and a plain pink tank top. She's more lean than you, with her legs being a defining feature she proudly shows off. You, however, are currently wearing a white t-shirt, a short blue skirt, and... Well, no underwear, of course, because of an earlier situation. Overall, you're both pretty comfortable with how you look most of the time, for probably a good reason.

"So we'll go back and forth, with the classic thing of asking each other truth or date, but we need a punishment for refusing, and we can choose ourselves how the other will be punished. Wait, wait! I know what you're going to say. Nobody's coming in here, and I won't make you go outside. Not this time," she says with a wink.

She notices your uncertainty, and chimes in again. "Alright. How about this? I'll let you walk home in one of my pairs of panties. No tricks, either. That's the prize for making it through. If you fail, we'll get the fun punishment over, and I'll let you have the panties anyway. I know. I'm so nice~! Actually, how about I let you wear _anything_ home? Even my pants. I don't care."

You can be completely covered in any way you'd like if you just participate? And it's a way to pass time? Well, you figure you might as well. She clearly really wants to play with you.