At first nothing happened. Derek decided to tuck both his balls inside the sock as well. The elastic at the top of the sock seemed to tighten around his entire package almost like a cockring but his 7 incher and average balls still seemed completely lost in the huge white sock which hung down to his knees.
Suddenly Derek felt the elastic around his cock and balls grow tighter. He felt the head of his semi hard cock sliding further down the inside of the sock, the head starting to rub the inside of it more and more as it grew longer and thicker. Close to the base, the white sock began to stretch and bulge obscenely as his balls expanded to the size of large eggs.
Believing himself to now be hung as big as he had always wanted to be, and anxious to see his new equipment, Derek reached down to pull the sock off. To his surprise it seemed stuck around the base of his cock and balls and refused to come off no matter how hard he tried.
By the looks of it, his balls were now approaching the size of baseballs, and Derek's mind raced with thoughts of how big he might end up, and that maybe this wasn't such a good idea afterall.
He was so focused on his large growing balls that he had almost forgotten about the huge python that was still attempting to fill it's cavernous white prison. When he looked down, he saw the very end of the sock beginning to bulge out, taking the shape of an enormous bulbous cockhead...his cockhead! As it approached the dimensions of a large orange he suddenly felt the entire length of what was once the baggy white cotton sock, pull tight and begin to stretch.
To Derek's shock, he realized that his once average 7 incher now entirely filled a sock that had to be at least 18 inches long and over 10 inches around! He felt something pressing against his thighs and noticed that his balls had actually freed themselves from the sock and had grown to the size of grapefruits hanging in a big fleshy sac!