Ty turned for the door and was about to head downstairs to June when a wicked idea caught his fancy.
"Although..." Ty turned his head to the sleeping bit titted blonde. "You're in quite the position to manipulate, aren't you little sister?"
Ty chuckled as he turned and closed the door behind him once more. He stood at Dusty's bedside staring, enjoying the view. His 11" cock began to swell once more in excitement. Here was this beautiful woman he had created out of his asshole step brother, and she was like clay for him to shape into whatever he desired.
"Let's see if I can make you bigger like I had wanted."
The sleeping girl stayed motionless except for the subtle and steady enlargement that began to pulse through her form. Little by little, the blonde began to grow in proportion. From 6'2" she expanded on the bed to 7'0.
"Gooood..." Ty whispered, grinning. "That's it, honey. Turn into a giantess." He had always had a thing for giant girls. Now he was getting one as Dusty grew to 8'0. Her legs dangled off the edge of the bed. "Keep going..." Ty encouraged, watching with keen delight as the girl kept growing and growing. Soon, she was straddling her entire bed, back against the wall, legs dangling out in front of her to reach the corners of her room, arms dangling on the floor.
Ty stared in fascination as her head brushed the ceiling and she hunched over a little from her sheer size. The bed began to protest her weight with metalic groans and her knees began to push up into the air. She was nearly 25 feet tall! "That's enough, sweetie." Ty beamed, staring at the enormous woman on her bed. Her growth stopped and the giant woman happily slept on, totally unaware she was now the biggest girl in the world.
"Hmmm..." Ty rubbed his chin. "I think I'm going to enjoy this a bit..." Carefully stepping over Dusty's huge thick leg, Ty crawled onto the bed to get an up close look at the giantess. She was even more beautiful at this size, and her huge tits were goddess-like. Ty stood up and reached her boobs with his hands, gently caressing and stroking their massive flesh. In response, Dusty moaned in her sleep, smiled, and her nipples grew pointed and stiff. For good measure, Ty grabbed a nipple in each closed fist and gently caressed them, sighing dreamily.
"Oh, this is nice." Ty laughed. "But we'll have to try this sometime later." He stepped off the bed and back onto the floor. "Let's see if I can reduce you now."
Of course, Dusty began to shrink down. She returned to her original size and Ty sat on the side of the bed, watching the process with curiosity, as now the girl began to get smaller. With gentle hands, Ty picked her up like a toy as she fell to four feet tall, and cradled her across his lap and in his arms. She was as small and light as a child soon enough, and Ty held her close to his chest. Soon she was no more than two feet tall, maybe the size of a child's doll, and then she was a barbie at one foot. Ty gently hefted her into the palm of his hand and marveled as she shrank down to an action figure in his palm. She became smaller and smaller until she was just a spec on his hand. "Okay. Stop, Dusty. I don't want to lose you."
The bug sized girl stayed put. "Now..." Ty smirked. "Let's have you back to your normal size." Dusty responded by growing again, soon back up to being cradled in Ty's arms. The 20 year old took advantage of this time to fondle her little titties and caress her body, to which the blonde again smiled and moaned. As she got bigger, Ty sat her between his legs, his cock pressing into her back, and played with her breasts some more. As she came to three feet tall he began playing with her pussy, rubbing her tiny clit with a giant finger, and grinning as she began to squirm and gasp form his touch. As she got bigger and bigger, Ty continued touching her, rubbing her pussy, and playing with her tits. He made her cum in her sleep as she returned to her original size of 6'2", then gently laid her back down on the bed.
"God yes." Ty stared, laying next to her. "I can control size just fine. So... now what should I try?"