Interrupting the sound of the boss fight music coming from my TV and the slap of my fingers on the plastic controller buttons, the door to my room creaked open. Without pausing, I glanced from the screen to see my little sister standing in the doorway. "Go away. I'm busy, twerp," I told her. "It's past your bedtime anyway. What are you doing up?"

She pouted in my peripheral vision, holding her toothbrush. I was too focused on the game to notice or care that it was her second, special brush. "I'm sorry to bother you, big brother. It's just that... I need your help, with my teeth."

I gave her a sideways glance. "You're old enough to brush your own teeth."

"Not these teeth." She tapped against one of her front teeth before closing her mouth and then tracing a line down to the front of her pajama bottoms. "Those," she said.

"Oh." My sister had a very unusual condition: vagina dentata, a set of teeth growing out of her girl parts. Like any other teeth, they had to be brushed, despite how sensitive the area was.

"I know it's weird, especially because you're my brother, but you're so good at helping me brush down there! I can never get everything by myself and it feels so good when you do it for me. Please, pretty please, would you help me?"

Making up my mind for me, my TV speakers played the distinctive jingle informing me that my character was dead. I sighed, set the controller down and climbed off the bed to follow my sister into the bathroom.

She smiled under the bright bathroom light, pulling down her pajama pants and looking at me doe-eyed as I spread paste onto the brush. My instinct was to look away as she next removed her panties but that would do me no good considering what I was here for.

I didn't have a basis of comparison for prepubescent girls, but her hairless slit seemed normal enough to me. It was only as she spread her lips and the pink folds were revealed that the oddity became apparent: rows of teeth lining either side of her entrance and further back in, more and more pearly whites becoming visible as she stretched her labia further apart. Most resembled molars but a few were more like fangs and some were tiny baby teeth, all glistening in the light.

"Let's get this over with," I said. As soon as I made the barest of contact with the brush, she let out a "Yeep!" and recoiled away. I groaned, looking at the sparkling pink glob of wasted toothpaste now on the tile and then making eye contact with her.

"I'm sorry, I'm sorry!" she said. "It's just so sensitive! Be careful!"

"Whatever," I replied, prepping the brush to try again. "Just keep still, okay?"

She nodded and pulled her curtains aside once more. She flinched as I started brushing, but didn't pull away this time. After a handful of broad, disinterested strokes where I was trying my hardest to fool myself into believing I was doing something far less strange, she wined, "No! Brother… you have to do it right. Please, you're so much better at this than I am. Just, go slow, okay."

Alight, slow and steady it was. As I paid meticulous attention to each tooth, slowly scraping the bristles before gliding onto the next, my sister began to wince. "Does it hurt?"

"N-no. It actually feels, uh, warm? You're doing fine, just keep doing that. Don't stop, please?"

She might have been too young to know what was happening, but she was getting off on this, it was undeniable. And she was warm too, with heat radiating onto my hand. Every stroke of the brush seemed to send shivers through her body as slickness flowed over her teeth and began to dribble down the outside of her slit. Her breath caught in her throat as the toothbrush continued to explore my sister's most intimate places.