Allison (a).

"Uncle James!!"

The pale, nude body of your 18 year old niece burns into your eyes as time slows down. The water is cascading down her back, soap suds hiding not much at all from your eyes, even as she rushes to cover herself with her hands.
"OH SHIT!" You yell, quickly backing out of the shower and shutting your eyes. "Allison..I'm so sorry. I thought Jenna was in there..."
"Jesus!" you can hear her panting over the sound of the water. "You... s...scared me!"
"I'm sorry...I'm sorry...I'll just... How did you get home? There are no cars."
"Riley... she dropped me off and went back out to get some stuff for us to have dinner tonight!"
"Jesus... Alli...I'm so embarrassed." You crouch down, back against the wall. "Are you alright?"
A second later, her voice pipes through. "I'm okay, Uncle James...you just...you frightened me that's all. It's okay. It was just a mistake." Her voice is calming down now.
"You're not going to..."
"I won't tell Momma, don't worry. It was just an accident." She laughs suddenly. "The look on your face... wow, that was actually pretty funny, now that I'm not scared anymore."
You give a nervous chuckle. "Yeah, thanks..."
You pull your boxers back on, standing up. In the bathroom mirror, you can see the shower door, reflected. It's pebbled, but you can see the indistinct, pale body of your niece. Your mind fills in the fuzzy outline with what you just saw. Flawless porcelain skin. Long, lithe legs and perky tits, just the right size for her petite body, not too small but not dominating her frame, and her red hair, so reminiscent of her mother's. You swallow hard and squeeze your dick, trying to push it down. That's your niece, you pervert.
"...Uncle James?" she stops moving, turning towards the door. "Are you still in here?"
"Yes...just leaving. Had to get my... my shorts on..."
"Were you... were you staring at me?" she sounds... you can't tell if it's fear or thrill.
"What? No..." you stutter. "No I'm leaving now. I'm sorry I bothered you."
"It's...." she pops the shower door open. "It's okay if you were, Uncle James..." she pops her head out. "I...." she bites her lip. "I kind of liked it."
"What?" you stare, jaw dropped. "Allison, that's not..."
"Appropriate, I know..." she's staring at you, now. Your chest and arms are bare, and your boxers aren't doing much to hide your tent. "I've always liked inappropriate things. BBC Porn, flirting with older guys.." she bites her lip. "Daddy almost grounded me for six months when I flashed his best friend Kyle at poker night. He doesn't come around anymore..." she sounds sad.
"Allison..." you start backing towards the door. Her eyes are getting a dangerous gleam in them. "You're my niece. I rode you on my shoulders when you were a little girl. I can't..." you swallow hard as she steps brazenly out into the bathroom.
"I'm not a little girl anymore, Uncle James..."
"Allison! Don't...if your mom, or dad...." you squeeze your eyes shut.
"Daddy sneaks around and cheats on mom..." she says defiantly. "And Mom knows... she caught him once. And she didn't do anything about it... why should I care what they think?" You can feel her, suddenly. She's standing right in front of you. Your back thuds against the door.