Celeste doesn't answer right away, she seems to hesitate, divided between curiosity, envy and doubt. Suddenly, she licks her lips, a sign of excitement that does not escape you. "Well... I don't know if this is really a good idea... It's a little extreme."
"Say always," you retort, a little worried.
"Why don't you test a full set of clothes? That way you could be 100% of what I wear: clothes and accessories. That way you would have the full experience of my femininity."
You don't know what to say to that. You would never have been able to imagine something like this and you're amazed that Celeste would even consider it. The idea, however, is very exciting, though terribly intimidating. You would be all over your sister at once, in contact with her entire body...
But she insists: "So, what do you think? I can see you're scared, sorry, it was stupid of me to offer you that and..."
"No no, not at all," you answer hastily. "In fact, I'm intrigued by it, and I'd love to get to know you that intimately! But are you sure you don't mind? I mean, I'll be in contact with..."
"It's no bother to me," she immediately exclaimed, before biting her lip, seeming to fear coming across as obsessed or worse, a cheap girl. "Uh, I mean, for you, I'm willing to do it. I realized from listening to you how much I care about you too."
You blush: "That's sweet!" Then, taking a deep breath: "Well, what set of clothes were you considering?