She pulls her underwear down, and notices you.

By: Cheeze111

The growing bulge in her underwear was starting to strain the fabric. Kim knew she was home alone. Well, her brother was still there, but he should be fast asleep. Every twitch of her cock sent a small wave of pleasure through her, coercing her decisions. It didn't need much pushing, the romance novel already providing plenty of enticing thoughts.

You felt your world shake as the growing shaft began to rise up. The cloth prison kept it at bay, but there was just enough space now for you to try and make a move. You squirm desperately to escape the sweltering heat. But her scrotum was tough to navigate. Having been forcefully pressed into it made the supple skin stick to yours, adding even more difficulty to your escape. You could hear a soft moan overhead. You had to get out of here now. What if Kim realized you were down here? You didn't want to find out what she'd do in that situation. But your heart sank when the fabric walls of her underwear began to move.

"Hmmmm..." She hummed with delight as she freed her cock from the restrictive panties. It looked as hefty as ever and Kim didn't waste another moment wrapping her hand around the shaft. Slowly she began to pump it, calmly running her fingers along the stiffening mass. It reached full mast soon enough and she gasped as she felt her balls ache with pent up release. But her pleasure came to a sudden pause when she felt something.

You watched in horror as the panties were pulled away and discarded. You were still stuck to your sister's scrotum and she looked eager to start playing with herself. The fact she had a cock that would put yours to shame at normal size mattered less by the second. If she found you here she might think you're a pervert trying to sneak a peek at her crotch. You watched her hand go up and down along the shaft, covering more and more of her manhood every time. It was inevitable that she would hit you. You finally make some progress, peeling your arms free from the smooth sack. But as you try to free the rest of you her hand slides down far enough to mash you back into the base of her package. The shocked gasp overhead confirmed that it was game over.

"What the..." Kim mused, surprised to feel something on her balls. She cups them in her hand and peels away the strange thing plastered against them. Did some bug fall into her underwear? Or could it really be... She brought up her hand and opened it, staring in amazement at you.

"Will?! How did you get here? And you're so tiny! It actually worked?!" She was overwhelmed with surprise, but her reactions only deepened your fears. What did she mean it worked? Was she responsible for your diminutive stature?

"Kim! What the hell is going on? I got shrunk and you've got a dick?! What is happening to me?" You cried out, hoping your tiny voice was still loud enough to be understood.

"Oh Will, I was going to show you eventually, but I guess that time has passed. Yes, I am a futanari, just like all the women in our family. We've got dicks alongside the usual parts and they're pretty hefty too." She said, boasting a little. She knew how she measured up against you before you shrank. "As for your new size, I read something online about our cum having some special properties if distilled and processed. I spiked your drink last night, not believing it'd have any effect. But now you're like the size of my pinky!" She seemed unnervingly cheerful about her act.

"What?! Well congratulations! Can you unshrink me now? I'm scared." You snap back, trying to hold back the worst of your sarcasm. Worryingly she just laughs at your suggestion.

"I don't think so. I've been fantasizing about this for far too long. A little Willy to play with my big willy. And would you look at that, Big Willy is so eager to play with you too." She slowly brings you back down to her shaft. You throw one scared glance over your shoulder, looking down at the immense pillar of aroused flesh, before pleading with Kim again.

"Please, don't do this. You'll hurt me!"

"Oh hush now, I'm sure you'll be fine." She replied, her voice heavy with desire. She wasn't going to delay another moment. The tip of her dick was glistening with pre. But what deep, hidden fantasy does she have in mind with her shrunken brother?