Kat put her hands on her hips and started slowly shaking her large breasts side to side as she laughed at her brothers predicament. 

"Seems like a tiny pervert found his way into my bra." Kat said. "Do you like my big, big boobies?"

Jimmy could feel her nipple harden as he was shaken back and forth by her bouncing boobs. 

"No! It was an accident! I got stuck in your bra at the changing room!" He tried to explain. 

"You were watching me change? You really are a little pervert." She said. "Your so tiny and weak, my nipple is bigger than you." Kat grabbed her other breast and started massaging her nipple as she bit her lip. 

"I must be like a living goddess to you now. So powerful and sexy." She said.

Kat stepped into the shower and turned on the water, Jimmy still dangling from her nipple. 

"Kat! What are you doing? Get me off of here!" Jimmy yelled. 

"I don't think so little toy, your goddess wants to play." She said as she began to pour liquid soap on her body. 

She plucked Jimmy off her nipple and began using his tiny body as a loofa, rubbing him all over. 

The soap covered his body, as he was rubbed all around her breasts, around her stomach, and on each plump ass cheek. Her soft skin made the entire experience more mentally uncomfortable than painful. His sadistic sister was truly enjoying having so much power over him. 

After a few minutes she held him up under the shower stream, rinsing him off. He looked at her face and saw her large grin and eyes filled with desire. 

"You look so cute at that size, I could just eat you up." She said. "In fact…." Her mouth opened and she stuck out her pierced tongue. 

"No! Please don't eat me!" Jimmy yelled in panic. 

Ignoring him, she dropped him on her tongue and sucked him into her mouth. 

He grabbed her piercing to stop her from swallowing him, but it was like riding a wet, wild bull. He was thrown around her mouth and covered in saliva. If it wasn't for the nano bots making him more resilient, he'd surely be a broken and bruised mess. 

The rumbling coming from deep in her throat let Jimmy know that Kat was laughing at his predicament. After what seemed like an hour, her mouth opened and light flooded in. 

Her massive fingers reached for him and plucked him out. She was grinning madly at him. 

"Look what I grabbed while you were having fun in my mouth" she said holding up a big purple dildo and some rubber bands. "Having so much power over tiny people has been my fantasy for a while, and I'm going to enjoy every minute of it."

"Kat! I'm your brother! You can't do this!" Jimmy yelled. 

Kat laughed at his pleas. "We aren't even the same species anymore, little bug." With that, she ties Jimmy to the dildo with rubber bands, trapping him in place. 

Jimmy struggled and screamed to no avail as he was lowered to Kats massive pussy. She slowly thrust him deep inside her, covering him in her juices. The soft walls of her insides pressing against him. After he went in as far as she could get, things got much more violent. She started to rapidly thrust him in and out, as fast as she could. He could hear her moans whenever he was pulled out, and she was clearly enjoying herself. 

It wasn't long before he could feel her insides tighten and pulse with pleasure, and Kat let out a much louder moan. She stop thrusting him and slowly pulled him out. Kat held him in front of her face and laughed at Jimmy's exhausted looking form. 

"Was it good for you too?" She asked sarcastically. She quickly finished rinsing off in the shower and got out and walked to her room. 

Jimmy couldn't believe what had just happened. Kat had just made it very clear that he was not even a person to her anymore, and just a plaything. They had never really gotten along, but this was too far. He needed to figure out a way to escape. 

Jimmy was dropped into her bed as she changed into her night clothes, a thin nightshirt and tight short shorts. She also pulled out a single sock. 

"This is another thing I've been wanting to try out. You're gonna be spending a lot more time where you belong, under my feet." Kat said, waving the sock around. 

Jimmy got up and tried to run towards the edge of her bed to try and escape under it, but his exhausted body could barely move and he was quickly snatched up. 

"I don't think so. Now be a good pet and make sure to wiggle a lot." She said as she dumped him in her sock. She sat down and slowly slid her small (to her) foot into the sock, wiggling her toes in expectation. 

Jimmy watched as the 5 massive toes made their way to him. There was no place for him to escape, and they quickly wrapped around him. The still slightly wet toes scrunched over his body repeatedly as he struggled to get out from under them, but they would let him go. Despite just taking a shower, he could smell a ripe stench from them. 

Kat layed down on her bed, still glowing from her shower "massage" and giggled to herself as she wiggled her toes. 

"This is a dream come true. I can't wait till school starts up again. Looking down on a school full of tiny bugs is gonna be so fucking hot." Kat said to herself, imaging all her old schoolmates in the palm of her hand.