For as long as he remembered, Ty had always been fascinated and aroused by shrinking. He had stumbled onto some pictures of shrunken women when he was younger, and had enjoyed masturbating to the idea of holding a tiny little girl in his hand.
"Listen... Dustin... I'm going to do something a little more weird, okay? I just want to try it."
His step brother turned young step sister blinked and stepped far back against the shower wall, trembling. "N-No... no more, Ty. Please. Just change me back."
"Shrink." He commanded, willing it, ignoring Dustin's pleas.
"What?" Dustin cried out in his now girly voice. "S-Shrink?" Too late the little girl realized what was happening as she watched the room suddenly growing around her. "No!" Dustin squeaked, her voice even higher. "Wait, no! No! Don't shrink me!"
Ty came closer, amazed as naked little girl Dustin was now half the size she had been. And still becoming smaller.
"No!" Dustin screamed. "NO! MAKE IT STOP!" Her voice was getting higher as she got smaller. And with a grin, Ty realized she was getting cuter too. Forget that moments ago Dustin had been Ty's jock douche of a step brother. Now he was witnessing a real shrinking girl. And it was very exciting for him. He reached down and gripped little Dustin in the tub as she became just a foot tall.
"NO! NO! Take your hands off me!" Dustin screamed, kicking little legs, but Ty easily picked her up, much to her wide eyed horror.
She became a toy. Just three inches tall, and Ty whispered "stop" gently. The tiny little female struggled in the grasp of Ty's closed hand.
"My God..." Ty whispered. "You're so little..." He leaned in closer and opened his hand, watching teensy Dustin scramble in his palm, her warm bum and hands tickling him. "So cute."
Dustin watched in horror as Ty's giant fingers caressed her little girl body. She turned in disgust.
"Just think." Ty whispered again. "This morning you were my bully. And now you're my little plaything."
Dustin only stared up, glancing around nervously. Her scale was coming into focus, and she felt ill.
"And now..." Ty grinned wider, pulling out the waist of his pants. "I'm going to play with you."
Dustin didn't comprehend, only let out a tiny squeak, as she fell from Ty's palm and into the front of his underwear, tumbling down sparse pubic hair to rest against a hard throbbing penis.
At first, Dustin struggled, and then realization set in. The three inch girl stared in disgust at the sight of a huge towering penis over her, and slid down into the crotch of Ty's underwear to rest her legs under his balls. She gulped as the waist band closed and put her in darkness.