"Hey, Matt, you should try it now!" Katie said.
"Uh... okay... I'll let you pick the setting for it." Matt responded.
Matt slowly stripped down to his boxers, since he was more shy than Katie was. Katie smiled when she noticed his large bulge. Matt stepped into the machine, and Katie entered in Natural Grow, Level 2.
Matt's body was blasted with hormones, causing him to gain an erection. Then he started growing. He slowly inched taller, and started to gain muscle mass, gaining a six-pack of abs. For some reason, his cock grew a few inches, so when he was done, Matt was 6'5.5", and he had a 10 inch cock that was starting to strain his boxers some.
"Y'know, to be honest, I don't think teenage boys going through puberty would have their manhood grow 3 inches when they grow 6 inches taller..." Matt said.
"Oh well! Whatever the case, since our parents will be gone for a month, we can tell them that we just had a massive growth spurt!" Katie responded.
"Wait, what about my sister?" Matt asked.
"I'm sure we'll figure something out."
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Meanwhile, Matt and Katie's friend, Riley, and Riley's older sister, Cynthia, were walking over to Matt's house.
Riley was younger than the two, being 14 years old. She was 5'4" and 130 lbs.. Riley had large breasts for a girl her age, having large C-Cups that were almost D-Cup breasts. She also had black hair that went to her hips. For some reason, she had a sex drive, and would try whenever she could to get at Matt's manhood.
Riley's sister Cynthia was 16, and she stood at 6 feet tall, and had gorgeous DD-Cup breasts. She was a bit stronger than the average girl, having done a little weightlifting, but not much. Cynthia had black hair like Riley did, but she had a tendency to dye it green. While Cynthia had a sex drive too, it was more due to her age.
While they were walking, Riley was telling her sister about the size of Matt's endowment.
"I mean, it's pretty big, and from what I heard from his doctor, he's just started puberty, so think how big it's going to be!" Riley said.
"Well, at least our parents our away for the month. I don't know why, but I think a lot of kids our age are having our parents leave for a little bit." Cynthia responded.
Riley just shrugged, and they finished walking to Matt's house. Riley knocked on the door.
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"Someone's at the door." Katie said.
"I'd... uh... rather not get the door..." Matt said.
Katie nodded, remembering her boyfriend's shyness, and then left for the door. When she opened it, she saw Riley and Cynthia, who looked at her in shock.
"Well, you had quite a growth spurt! I wonder how Matt feels about that!" Cynthia commented.
"Hey, uh, Katie... why do you have so little on?" Riley asked.
"Oh, I'll show you! Come on in!" Katie said.
When they arrived at Matt's room, Cynthia looked at Matt's tented boxers in surprise.
"So," Katie said, pointing at the machine, "we found this machine that allows us to change size! It even allows us to grow naturally, making it look like we had a growth spurt!"
"Wow! Can I try it right now?" Riley asked.
"Um... later. We were going to try something else first." Matt said.
Matt and Katie got inside the machine, where Katie set the machine to Grow Level 4. Pressing the start button, the two teens started to feel themselves grow. Katie's already tight bra started to tear, soon being ripped apart by Katie's growing boobs. Her panties quickly followed suit. Matt's boxers managed to hold up better, though. The two kept growing taller and taller, until their heads bumped into the 10 ft high ceiling, and they kept growing! By the time they were done growing, they were over twelve feet high, and Katie was so tall that Riley had to look up at her vagina! As a matter of fact, even Cynthia had to look up slightly at it! Riley looked at Matt's foot and a half long rod, clearly surprised.
"Wow! You two are huge!" Riley commented.
"Well, let's head out to my pool out back." Matt said.
"Well," started Cynthia, "if you two don't mind, I'm going to change into my bikini, and then I'm heading to the public pool."
"Yeah, sure, just don't use the machine!" Katie said.
"I won't." Cynthia lied.
The three left the room, leaving Cynthia to herself. Matt and Katie trusted Cynthia more than Riley, since although Cynthia did have a sex drive, she was more mature about it.
However, after seeing the size of Matt's monster, she wanted to see it without his boxers covering it. But she wanted to be discreet about it, so growing herself wouldn't work. So she decided to shrink herself for a little bit. Heading into the machine, she entered into the console Shrink Level 6, and set her final size to one inch tall. Before she pressed start, she went outside the room and took all of her clothes off. Stepping back in, she pressed start, and began to dwindle in size quickly. She reached one inch in no time, but when she looked at her gigantic surroundings, she realized how long it would take her to simply get out of the room.
"Well, shoot."
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Matt, Katie, and Riley were at Matt's pool. Stepping into the water, Matt found that even in the deep section, his cock was still a few inches above the water. Katie stepped in as well, only her legs getting wet. Turning around, Katie picked up Riley and lifted her high in the air.
"Hey!" Riley shouted, annoyed.
"Wow, you're so light! You feel like you're a small child to me!" Katie said, amazed at her own strength.
"Hmph, why don't you lift Matt's parent's extra car instead of me?" Riley suggested.
"Ooh, that sounds like fun!" Katie said.
She walked around the house slowly, making sure to not be seen, and grabbed the car. It was really small and eco friendly, so it weighed about 500 lbs.. Katie struggled a bit, but she was able to lift the car. Bringing it back, Katie placed it in front of Riley.
"Gee, you're super strong!" Riley said.
"Okay, I think we can go back in and let you try the machine some, Riley." Matt said.
"Yay!" Riley said happily.
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Inside, Cynthia heard the front door open. She managed to get out of the machine, but wasn't in any good spot to hide. Seeing her bra that she had taken off earlier, Cynthia ran towards it and hid in one of the cups. She was able to see the machine from where she was.
Ducking through all the rooms they went through, Matt and Katie reached Matt's room. Katie noticed the pile of clothes on the floor.
"Huh, I guess Cynthia didn't take her clothes with her. I guess she'll pick them up later." she commented.
Riley entered the room.
"Can I please pick the setting?" Riley pleaded.
"Ugh... alright, but just this once!" Matt said.
Giddy, Riley stripped down to her underwear, and went into the machine. From the inside, she selected a size. Katie looked at the control panel on the outside, and was shocked that it said Natural Grow Level 6, and was set to three feet! Before Katie could do anything, Riley had already pressed start, and the machine started filling her young body with loads of hormones.
Riley started to grow, her body developing supermodel curves. Her panties turned into a thong on her, and her breasts started to balloon up, causing her bra to tighten on her. Smiling, she felt over her expanding body, and was delighted when her butt grew enough to cause her panties to rip off. Her bra quickly followed, and soon Riley reached 8'4", looking like a giant amazon. She had gained some feminine muscle mass, giving her a sexy six-pack. As she stepped outside, she was disappointed that she still had to look up at Katie's breasts.
"Riley! What were you thinking? That growth is now permanent!" Katie said.
"Exactly!" Riley said with a smile.
"Well, I think it might be best if you go home now." Matt said, annoyed.
"Well, I'll be back," Riley said, stroking Matt's huge rod, "but I think I'll put on Cynthia's old clothes, or at least her underwear."
Riley grabbed Cynthia's bra, which, unknown to her, had Cynthia inside! She put it on, but it was very tight. Cynthia was pushed against her younger sister's giant nipple, and realized with some shock that when erect, Riley's nipple was bigger than she was! Cynthia tried squirming to get Riley's attention.
"Ooh, I see why Cynthia loved this brand of lingerie so much! It feels like its pleasuring my nipples!" Riley said, not realizing that her older sister was trapped in her bra.
She left, her beach ball sized boobs bouncing as she went.
Giantess World
Chapter End Notes:
Just a note: when giving ideas for future chapters, don't suggest that Matt or Katie be shrunken! Other characters are fine though, so please leave a review!