Frank decided to go looking through his brother's clothes to find something good enough to wear, which was a little hard, as he was now a year older than his brother. Going through his clothes, he managed to squeeze himself into a pair of boxers, albeit boxers that were slightly too small, given the new size of his package. He managed to find a shirt that was big enough as well, but squeezing into the pants was a total nightmare. It took several times of rearranging, adjustment, and pain in order to fit in, but it looked like he had stuffed something into his pants.
Frank shrugged, as he looked at the size of the clothes. He had better get some new ones. He remembered though there was a clothing store nearby. He reached behind one of their picture frames that he could reach now, because his mom had told him there was a credit card there that they could use only for emergencies. He was pretty sure this qualified as an emergency.
He arrived at the store, although the amount of looks he got made him quite uncomfortable. Once he arrived, he quickly got clothes that were too big for him, as he had a feeling he might be too big for them. He quickly paid and headed to the dressing room, but he started feeling tight all over again! He was growing again!
He quickly shut the dressing room door, and tried frantically to get his clothes off, but to no avail. Very quickly, his growing biceps shredded the sleeves of his t-shirt, and he was bent forward as his back muscles grew, ripping the back of his shirt, followed by the front, a la abs and pecs. His pants fared no better as his growing legs quickly burst them at the seams.
Frank bent down as the final part took place. He grabbed his large bulge and moaned as it shuddered, hardening, and ripping straight through his tight boxers, and he gripped it with both hands, as it pulsed. He thrust his hips forward with every pulse, and with every pulse, it surged larger and larger. This was his largest growth spurt so far! He looked down in near fear as his cock forced his hands open, growing from 13 inches to monstrous 21 inches! His balls surged larger as well. He couldn't resist as he leaned forward and licked his cock, gently sucking it, until it was too much. He came, and he came hard, cum shooting out of his cock like a fire hose.
He laid back breathing heavily, now a 17 year old, with a giant log between his legs, hanging down to his calves. It's a good thing he got bigger clothes...