Yawning, you make your way groggily into the kitchen. Your sister is already in there, doing her post-workout stretches. Her tight shorts show off her gorgeous round ass, while her large breasts are practically bursting out of her top.

"Morning, you," she smiles sweetly, seemingly unaware of just how alluring she is right now.

You've always thought she was attractive, but lately you can't help but notice her in a different light. Maybe it's because you both just turned 19 and are about to start college together... or maybe it's something else entirely. Either way, there's definitely an undercurrent of sexual tension between the two of you that you've never experienced before.

With a small smile and a shrug, you reply with "Yeah... but that doesn't mean I can't look at you."

"Uh... I..." Katie blanches, looking both flustered and turned on at the same time. It's obvious she's never been propositioned like that before, let alone by her own brother!

Katie hesitates for a moment, trying to process your offer. Part of her wants to know what it would feel like... but another part of her knows that this is completely wrong on so many levels. "I-I don't know," she stammers, looking at the floor, clearly conflicted. "This doesn't mean anything, right? We're not actually related or anything..."

That doesn't make it any less... strange. But part of me still wants to know what it would feel like... if we could just explore this together. I trust you, but I need some time to think about this. Maybe later tonight?

Katie nods slowly. "Okay... let's just finish breakfast and get started on the day, then we can talk about it tonight. I still need some time to process this." Her heart races with anticipation as she pours herself a cup of coffee, wondering what might happen between them later on.

Later that night, Katie finds herself in her room, unable to stop thinking about your earlier proposal. She's never been this turned on before, and the thought of exploring her sexuality with you - someone she trusts completely but also knows is off-limits because of our relation... it's both exhilarating and terrifying. Finally mustering up the courage, she decides to confront you about it once more.

Tiptoeing down the hallway quietly, she knocks on your door gently before opening it just a crack. "Hey? Uh... can I come in?" Her voice is soft and uncertain as she peeks into your room.

Taking a deep breath, she slowly pushes the door open further, stepping inside your room. The light is dim, casting shadows across your body as you lie on the bed, watching her with piercing eyes. Her heart races in anticipation of what might happen next. "I... I've been thinking about earlier," she admits softly, biting her lower lip nervously. "And I guess... I want to know what it would feel like..."