The thick muscles in Kurt's arm held Erik in place for a while, but the younger brother had been in this situation before, and knew how to get out of it. Moving back and forth as much as possible, he simultaneously banged his foot against Kurt's shin and pried at his thumb, forcing a quick but loud yelp of pain to escape from Kurt's lips and his grip to loosen slightly. Not much, but just enough for Erik to wriggle free and slip away. "Can't stop me now!" he exclaimed, dashing out the door and slamming it behind him. The sound of his small feet running faded down the two flights of stairs to the basement, where Kurt kept his weight set.
"Erik WAIT!" Kurt cried after him, grabbing at the door handle. "Damn thing always sticks!" It took a few seconds to yank it open, and Kurt then ran down the stairs to go after his brother. Hiro, still not used to his bigger size and partially constrained by the tight remnants of his clothing, followed behind him awkwardly.
By the time both of them got to the basement, Erik had already worked up a sweat, struggling to lift the curling bar. The weight that Kurt had left on it was far too much for the twelve-year-old to even budge, so after a few seconds he gave up and ran over to the hand weights, picking up two ten-pounders and swinging them back and forth wildly. "With this workout, I bet I grow way bigger than Hiro!"
His taller friend rolled his eyes, grinning. "Always a competition."
Kurt ran over as fast as he could and pulled Erik by the shirt collar. "Put those down!" he cried, yanking one with his free hand while causing Erik to drop the other, barely missing hitting Kurt's foot. "What do you think you're doing??"
Erik just ignored his brother, feeling a wave of dizziness wash over him. "Oh boy, I think this is it!" he cried out. With Kurt still grasping his shirt, the mess of Erik's red hair began rising upwards. It looked like he was taking a deep breath that never ended, his body expanding outwards and filling out his clothing. His midriff quickly became exposed, and his toes started ripping holes in his socks.
Within twenty seconds, he was already as big as Hiro had gotten, but his growth was nowhere near done! The sound of fabric tearing filled the air as the seams down the sides of his pants ripped apart, revealing his bright green boxer-briefs containing a sizable bulge. Kurt, still doing his best to hold onto his younger brother's collar, now had to reach up slightly, and seconds later that part of the shirt ripped off in his hands.
"This is soooo coooooool..." Erik exclaimed, his voice booming throughout the basement yet no less childish. He looked down his body, seeing his tattered clothes fall to the ground, except his underwear, which only had a matter of time remaining. "I'm so much bigger than-- OW!" He winced as his head bumped into the ceiling, shaking the house slightly and causing the framed posters on the wall to rattle.
Luckily, his growth seemed to stop there for now. Slouching slightly to avoid hitting his head again, Erik surveyed the room, thrilled to see that Hiro and Kurt were both eye level with his chest. Turning to Hiro, he flexed a little for his friend. "What do you think, Hiro?"
"It's-- it's pretty cool," the blushing Asian boy responded, averting his gaze slightly but not fully taking his eyes off of his friend. "Do you think we'll get bigger?"
"No!" Kurt quickly replied. "Don't even think about trying! You're already about to outgrow this room, Erik. What would happen if you outgrew the house?"
"Yeahh..." The twelve-year-old seemed to relish the prospect more than Kurt had intended.
Kurt cursed his parents for not responding to any of his calls or texts and racked his brain trying to think of what to do. If he forced the kids to stay home, they would be concealed from anyone else seeing, but if something triggered their growth again, that could prove disastrous. He could take them somewhere, like a hospital or the doctor's, but that ran the risk of having other people see the suddenly-giant boys which could prove problematic (not to mention Erik would have problems fitting in the backseat of his car). Or, they could just go outside and hide out in the woods behind their house for a while, until hopefully his parents got back in touch with what to do next. After a few minute's contemplation, he decided on...