"You want me to do what?"
Theo rolled their eyes. "You heard me, take a handful of my pills, so your boobs grow."
"I... I can't believe you'd suggest that!"
"Well, you're the one who spent all day yesterday at the wedding complaining about how much bigger your sister was, love. It felt like that was all you talked about."
"Uh, I guess I can't argue with that," Susan muttered. "You know what? Fine."
She put out her hand, and Theo knocked four pills out of the bottle, paused, then added two more. "That should be enough for some of the growth to stick."
Susan looked at the six oblong pills with a sense of apprehension. "Won't an overdose like this be dangerous?"
"Maybe? I mean, what's the worst that can happen?" Theo said with a tiny shrug. They were barely four-and-a-half feet tall at the moment, their body perpetually shrinking due to a childhood mishap. It made them so cute most of the time.
"We could crush the city maybe?"
"That's not--Look, how ‘bout we both do it?" Theo poured out six pills for themselves. "So that you know its safe."
"Yeah, for you. You're the one who has to take the dang things. I could end up a giant forever!"
"You won't stay huge forever, Susan. Even for people without my condition, they have never seen a permanent increase in size more than ten percent of the growth. The body isn't capable of dealing with the level of exaggeration."
Susan glanced between the pile of pills and her partner. "You're just looking for an excuse to see what happens, aren't you?"
Theo shrugged again and tossed the pills into their mouth, chasing them with several gulps of water. "I've taken ten at once before--you know what I'm talking about."
"Yeah, and you were, like, ten feet tall for three days! Fuck Theo, your cock was bigger than my arm for two weeks!"
"Aw, don't be like that," Theo laughed. "You loved me being that big--and now we'll both be big together. Just imagine it. We're going down to Barbara's next weekend for the summer party, and out of nowhere, you're going to be this peerless Amazonian woman. It'll drive her up the wall."
Susan looked down once more. There were flashes of just how popular her conventionally attractive sister was growing up, even before she exploded in the boobs. There were all those times Barb held that popularity over her head to make her feel like the younger sister instead. How come she missed out on that just because she was flat in comparison? How come she missed out on that because she had to work to help out? What was wrong with wanting to have had a little fun in high school--much less college? Taking these pills was only leveling the playing field now that she was on her own two feet. It was time she got to enjoy herself as the bigger sister.
Excited now, Susan gulped the pills down and let out a long satisfied sigh afterward. The massive dose took effect a moment later.
It began with heat in her chest, followed by a pressure that only grew as her bust started to swell. Her girls filled out her t-shirt and kept inflating, their volume increasing by leaps and bounds as her top's hem rose higher and higher. When the stretch cotton was pulled tight by her new boobs, the growth had stopped, but the heat was only getting hotter. She was already as big as Barb, and the ratcheting pressure promised she would be far bigger by the time this was over.
With another jolt of growth, Susan's boobs surged larger, and her shirt rode up over her expanding bust line. Her boobs were massive now, overflowing her splayed fingers and she could feel them spreading even more. Ever more enormous, they grew down her body like an avalanche. They flowed past her ribs, and she had to switch to cradling them in her arms. Then, with a body-quaking shudder, the growth halted, leaving her with an armful of warm, jiggling flesh.
It was then she realized the loose sweat pants she had been wearing were now pulled tight around her lower body. What was more telling was how the cuffs, which had pooled around her ankles before, had become stretched to their limits around her much-thickened calves. The living room's vaulted ceiling was much closer to her; she could reach out to touch it without getting the step ladder.
"See? Everything went great?"
Theo's extra two pills had not resulted in much more height, but it had given them even more curve. Their growth had taken the volume of their teardrop-shaped tits way past their waist and nearly to their considerably widened hips. Theo's boobs had become so massive, that the pink head of their greatly enlarged cock bobbed against their undersides.
Susan opened her mouth to speak and then felt a wave of intense soreness. It was like the stitch from running too long, but she felt it from head to toe. From the face Theo was making, they were experiencing it as well.
"Why don't we go lay down?" Susan gasped.
"I was just going to suggest that, love. We can play later..."