Ty was 16 again, and was starting to feel it more keenly. Under his breath he said "I wish to grow back up to 20 years old, but for everyone but Dustin to think I'm 17." He smiled innocently under Dustin's glower. Mark was too busy stuffing himself to say anything. "Obviously only Dustin will notice my growth..." As if that triggered the change, Ty felt nice and warm inside again. Having already grown to a 20 year old's body, then being a large 16 year old, he was about to age 4 years again - and that meant more mass.
Dustin seemed to know something was going on. Not that Ty was bothered, of course. Ty felt his whole body getting warmer, almost shaking under what was to come. It was slower than before, but Ty felt himself getting taller. His boxer shorts got tighter not from his slightly larger waist but the growing cock stretching the fabric even further. His balls got even heavier, and the general tightening just made him horny.
"Dad, look!" Dustin pointed at Ty. "He's getting taller! Can't you see?"
"Dustin, I've told you before. He's tall for his age. You might catch up. Now finish your breakfast." Mark returned to his own with a shake of the head. Ty just shrugged. His torso was getting thicker, his pecs jutting out even more and a firm six-pack forming. His shoulders were wider than average, and his biceps were impressively thicker. His hands were even bigger than before - so were his feet, he thought with a wriggle. His knees just banged the table as he stopped getting taller, about 6ft 3 or so. Ty adjusted his stance as his hefty legs gave his pulsing dick even less room. Dustin only watched, gaping slightly. Ty felt his chest, face and crotch itch. With a feel, he knew he was sporting some mean stubble so early in the morning. His chest was even hairier, if not too hairy, and as for his cock... Ty had some trouble willing it to die down again. It was certainly hairier down there though. The same went for under his arms, and his arm and leg hair. Mark sometimes joked about June going with an Italian milkman, Ty thought with a grin.
"Dad..." Dustin began.
"Dustin! For the last time!" Mark growled over his food. Ty, having had as much fun as he wanted for one morning, stood to go to his room. In the mirror he saw his masculine, angular face. Damn, he was ripped as well. His thick neck made him look a bit like a wrestler, maybe. "Ty, I'm pretty sure we got you some XL boxers... could you at least wear them downstairs as you refuse to wear anything else unless you absolutely have to?" Ty looked down at his bulging crotch, tugging enough on them for the top to reveal some dark hairs too thick and spread to be the treasure trail.
"Whoops. My bad." Ty replied in a deep baritone, putting on his winning smile. As he headed upstairs he heard Mark saying "I hope he doesn't have another growth spurt anytime soon..."