As Derek's balls continued to swell even larger, he could feel their weight increasing; expanding and stretching his bloated ballsac even more...sagging further down every second as if it were 2 huge fleshy balloons, stuffed inside an even bigger one; while they were all rapidly being filled with water!
Derek and Ben could only watch in shock & amazement as Derek's cock also continued its insane growth in a similar fashion: The head of Derek's baseball-bat-shaped cock extended all the way down to his knees before it stopped growing in length; and then rapidly began increasing in both weight and girth; growing thicker by the second! The huge mushroom head expanded to the same size as one of his enormous, now softball-sized, testicles; while the shaft inflated to the thickness (AND weight) of a full 2-Liter bottle of soda, tapering only slightly at the base.
As the insane growth of his once normal, human-sized package finally subsided, Derek stared mindlessly at the freakishly oversized cock and enormous testicles he now possessed. He really was still trying to fully comprehend what happened; but as he felt the weight of that huge mass of male-flesh now forcing him to stand bow-legged, Derek was suddenly hit with the realization that regardless of how it happened...thanks to Ben, it was definitely permanent!