Not a chance.

"Are you done staring?" your topless sister asks, toweling her hair dry.

"Nnnno. No, I don't think I am. Why don't you show me the rest?" you reply, feeling bolder.

"Why don't I show you my coochie? Why do you think, John? Because you're my brother." Your older sister rolls her eyes so hard as she says that, ignoring the fact that a few minutes ago she said the same thing about showing you her tits.

"Do it anyway," you say. Wow, you really are getting bold. Sofia sighs, then obediently drops her towel, displaying her naked 19-year-old body for her horny younger brother. Beneath her big firm tits - and now fully hard nipples - you drink in the sight of your sister's narrow waist, flaring out into wide hips that frame her pink pussy. Her "coochie." And there isn't a pubic hair to be seen. Just smooth skin all the way from her neck, to her flat stomach, her mons, and finally to her sweet lips. And... do you see a hint of wetness there between her legs?

This feels so wrong, and it's so fucking hot. The forbidden sight sends a thrill through you, starting at the bottoms of your feet and running up your legs to your cock, which strains at your pants. And your sister notices.

"Jesus," she mutters. You thank him again. "I can't believe I'm doing this."

That brings up a good point. This is still an experiment. You should ask some questions. "Me neither, honestly. Why are you doing this?"

"Um, what?" she asks, startled. She must not have expected you to hear her.

"Why are you doing this?" you repeat. "Why are you showing your body to your younger brother? Including your coochie - which is beautiful, by the way." She blushes and half-covers her crotch with her hand. Shyness? Where did that come from?

She averts her eyes and doesn't answer. You just made your confident older sister stammer, then blush. You're drunk with power. "Well Sof? Tell me," you demand.

"I don't know..." Sofia replies quietly. "I do like how you look at me, how-" she glances down at your crotch, "-turned on I make you. I think..." Her voice firms as she gains confidence in her answer. "I think it feels like a way to practice flirting with someone I feel safe with. Someone I know won't take advantage of me."

That's... surprisingly honest and ****. Your lust ebbs a bit, just enough to affirm your commitment to not boning your sister. You want to be worthy of that trust. But your test isn't over yet.

"Flirting?" you press. "Is this how you flirt? By stripping naked for guys?"

Sofia rolls her eyes. "No, I mean... I don't know. Hooking up, I guess? Everything that comes after flirting. I'm not... super good at that yet."

Now that's a surprise. "Really?" you ask thoughtlessly. "I thought you were super experienced."

"You thought I was a slut?" she asks dryly.

Shit, that's not what you meant. Come on John, you're a safe, trustworthy younger brother. "Uh, no... No, but, what was his name..." You wrack your brain for the name of her high school boyfriend, the subject of those loud arguments between Sofia and your mother.

Your sister saves you. "Jacob. Yeah, he was great, at least the sex was. But now I'm single, and the guys I'm flirting with are older and more experienced, and..." She trails off.

"...And you're nervous," you finish for her.

"Yeah," she says quietly. The moment stretches into silence.

"Well, all right," you announce, loudly breaking the moment. "I'm happy to help. You can practice on me."

She blinks. "Practice having sex? With my brother?"

Okay, no, backpedal. "Well, maybe not that. But everything that comes after flirting. Practice getting a guy to want to get in your pants." You gesture at your tented pants.

Her **** moment behind her, Sofia barks out a laugh. "You just want me to tease you all the time but never get you off?" Your still-naked, still-stacked, she cocks her hip to the side and looks down at you with a sneer. "Wow, who knew my baby brother was a simp for his older sister. That's pathetic, John, even for you."

Anger floods through you. That bitch. How dare she? "Sof?"

"Yeah, John?"