As it turned out, the worst didn't happen. His giant blonde sister shrugged far above and closed the cap. She paused to stare down at the pile of clothes by the bed and looked around in curiosity. She couldn't have imagined that her teensy brother was staring up at her from far below completely nude and trying not to fantasize about his own sister.
Max heard a heavy sigh above and watched as Mandy shook her head in apparent embarrassment. "Man, look at me... going through little bro's stuff."
Mandy turned to leave the room. Even as Max breathed a tiny sigh of relief, though, he was suddenly startled as Mandy looked down directly under his bed and saw the tiny naked shape of Max lying there.
"What the hell?" Mandy squinted, blinking.
In terror, Max grabbed his mouth and stop himself from screaming in dismay and started to blush red hot as Mandy turned back and knelt down beside the bed for a better look. The tiny 16 year old bolted under the bed frame and hit the wooden brace behind him. He couldn't get away from her! She was going to see...
"M-Max?!" Came Mandy's horrified whisper.
Too late. The boy cringed and almost started crying with complete humiliation.
"Max..." Mandy suddenly blushed in embarrassment. She looked away frantically from her naked and hard brother and gasped hard. Mandy wasn't stupid. She looked back to the vial on the dresser and then peeked under the bed in sudden curiosity, her mouth agape.
"H-Hey, bro..." She whispered gently. "I-I won't tell anybody, okay? Just... let's... let's... holy fuck." She giggled as she made the realization in her mind and almost began laughing hysterically. "How did you get a real shrinking potion, bro?"
"Mandy!" Max squeaked. He began to shake uncontrollably, a cool sweat of fear causing all of his arousal to fade, and covered his shame in both hands. "Please!"
"Oh, yeah. Sorry." His sister looked away in shock, staring at the pile of clothes on her brother's bedroom floor in amazement.
"Uh..." Max squeaked in his high pitch voice. "C-Can you... can you go?"
"Yeah, sure." Mandy gulped in agreement. "Yeah, uh... sure. This never happened, yeah?"
Max said nothing, blushing red as his giant sister rose stories above him and turned for the door once more. She stopped a second time and stared down in Max's direction with a naughty look on her face. She raised her eyebrow. "Were you watching me?"
"Mandy!" Max screamed as loud as he could. "Go away!"
His sister looked out into the hall conspiratorially and slowly turned back again, quietly shutting the door and turning the inside handle to lock it.
Tiny max was mortified as she bent down again with a devious smile on her face and laid down on the floor to get a closer look at her little shrunken brother. "Maxy!" She giggled, "You were totally watching me, weren't you?"
"Mandyyyyy..." Max whimpered pathetically. He covered his groin and blushed deep red. It was obvious. His sister giggled in response.
"It's okay." She smiled comfortingly, which took Max off guard. "Is... have you done this before?"
Max gulped and tried to slink further back under the bed. "N-No, I just got this stuff. I wanted to try it."
That made Mandy smile wider for some reason and she blushed deep red on her cheeks. "Wow, that's actually... actually kind of cool! You shrank yourself!" She punctuated this with a hysterical laugh of disbelief and childlike wonder. "Look at you! You're really my little bro now, aren'tcha?"
Max stayed where he was and felt his heart beating faster and faster as his shame increased. He felt like a total freak.
"So, uh... how does it work, exactly? Are you stuck like this? Is... is there like a growing potion or something?"
"It'll wear off." Max whispered, his voice high pitched. He sighed, resigned himself to the fact that this was life now, and sat down while still clutching his dick.
"Whoa, cool!" Mandy exclaimed, still blushing and smiling wide. It was a warm genuine grin, he knew when she was putting up the fake smile. "So, uh," she finally asked, blushing redder, "you were under here checking me out like this?"
Still mortified, Max dipped his head and sighed. "Yes."
Mandy giggled and blushed deeper. "Max! I-I didn't know you... have you always... you know?"
"Mandy! Stop!" Max insisted, almost crying. "Please! Just go and let me... let me just... please."
"Hey, hey!" His giant sister consoled gently. "You know I can keep a secret, little bro. I'm just... curious, that's all."
"Yes!" Max spat suddenly, frantically, almost angrily. He felt his eyes growing wet.
"Huh." Mandy grinned deviously. "So, uh... that time last year when we were at the pool and we had to change in the family room, just me and you."
"Yes." Max gulped, going deathly white. He didn't know she had seen his wandering gaze leering at her.
Mandy giggled sweetly and put her head over her folded arms, staring at Max with unexpected playfulness. "I'm pretty hot, huh, little brother?"
Max stared at her in disbelief and wondered what exactly had happened. One minute he was about to enjoy shrinking, then Mandy came in. And now the world had become surreal. The poor shrunken teen stared in confusion if not outright disbelief.
"Mmm, yeah. I can't imagine how weird you must feel being turned on by your big sis, but it's okay, because I know I've got a really nice bod, long long legs, a great ass, and large perky boobs. Man, they've really just ballooned this year, huh? You should see how nice and big my nipples have gotten too. I don't think I'm even done growing yet!"
Max stared open mouthed in a mixture of revulsion and curiosity.
"Hmmm, I think you like that." Mandy smirked. "But you have to tell me something, okay? Just remember, this is our little secret. All of it. So you have to be honest or I'll..." She giggled again. "I'll tell everybody about you shrinking and checking our your sister. Like they'll believe me, huh? So I guess I just want to know."
"Okay. Fine." Max said with a defeated tone. He wondered how long they had been at this. Was his hour almost up?
"I promise, Maxy, this is just between me and you. Okay?" She waited for her brother's nod and giggled again. "Have you... have you ever... y'know... like, jerked it to me?"
Tiny Max fell completely aghast. "What?! Why would you want to know that?"
"Just answer the question, little bro. This is really neat having you so helpless, I'm not gonna lie. Tell me if you've ever pulled your meat thinking of your hot older sister."
"Yes." Max admitted meekly, staring at the carpet he was sitting on in his suddenly totally awful shrunken state.
Yet to his renewed surprise, Mandy's face lit up with delight and she stifled another giggle. "Shit, no way?! Really? Was it... was it good? Like did I get you all hot?"
"Yes." Max admitted again, gulping. Now he was genuinely interested. This wasn't... Mandy's usual gentle teasing. She really wanted to know.
"I-I kinda like that, Maxy." She bit her lip and gulped. "Mr. up and coming football can have any girl in his class but he likes his sister, huh?"
Max stared in surreal disbelief. Mandy motioned with one finger.
"Let me see." She grinned evilly. "How long do you have before you grow back?"
Max blinked in complete and utter bewilderment and looked down at his crotch. He could feel his dick swelling under his hands again.
"Yeah. Lemme see it." Mandy giggled. "Come on, buddy, just between us. I want you to enjoy your shrinking thing. I mean, it's a thing, right?"
"U-Uh huh." Max nodded, letting his sweaty palms fall to his size and his hardening dick spring up.
"Oooohhh!" Mandy smiled. "Look at that! Just from thinking about me, huh?"
Max nodded carefully, still not believing this was real.
"Okay." Mandy whispered. She looked to the door again to make sure nobody had heard her talking in her brother's room and giggled. She sat up, and to Max's total astonishment Mandy rose up on her knees, swung her long blonde hair to the side, and pulled her shirt off over her head. Max sat in shivering delight as he saw his sister's two giant tits supported in a red lacy bra.
"What do you think, Maxy? How huge are they to you right now?" She giggled again and blushed red, starting to shiver the same as he was. "Fuck, I can't believe I'm doing this."
"I-I don't mind." Max squeaked from under the bed, crawling out and staring up at the goddess that was his sister and her massive hills hovering above him.
Mandy stared down at her tiny brother and started to pant gently. She reached back slowly, her eyes wide, and gently unclasped her bra. Max's eyes widened and his dick began to bob in excitement as his sister slowly peeled off her bra and let it falls down her waist to the small in front of Max. The shrunken teen stared in utter bliss as he looked up at two tremendous naked breasts. They were huge at normal size. Melons. Mandy Melons, that was what his friends called her. To see each supple honeydew at two inches tall was the most titillating thing Max had ever experienced. As she had hinted, Mandy's areola and nipples were just as big as her huge tits. The front of her breasts were all nipple, and he watched in total awe as she lifted one of the huge mammaries to her mouth and gently sucked her own nipple. When she dropped it back down from her mouth, it was erect and straining. Poking out like the tip of her thumb. Fat, swollen, and long.
"Damn." Mandy stared in disbelief. "This is hot, Max. This is really fucking hot. I like this. Knowing that... knowing that you like this." Mandy slowly lowered her hand down palm up and gulped. "Come... come... closer. Let me pick you up."
"Shit, Mandy!" Max stood reluctantly. "This is like... a dream come true."
"Oh, yeah." His sister whispered. "Yeah, okay, buddy. Let's make it super special for you, then, okay?"