Brian's biceps writhed and flexed underneath the thin skin around his biceps as he pumped his massive cock up and down. Each stroke sent pleasure corsing through his body, and it made him want more. He concentrated harder and immediately felt the changes in his body. His traps grew larger, going above and beyond his ears. His pecs jutted further upwards and outwards, pushing his chin upwards. They were getting so huge that he could see them even when he was looking straight ahead. His nipples stretched larger and became more sensitive to the touch. His gigantic biceps grew larger as he involuntarily flexed them. They rubbed up against the width of his chest. Opposite them, his engorged triceps arched outwards in the opposite direction, connected to massive shoulders.
His lats grew wider and wider, pushing out the breadth of Brian's huge arms to larger and larger angles. His abdominals were growing larger also, a huge steel wall of 8-pack abs. They led down to a waist, that while still large, was small compared to the length around his chest and his legs. His legs! They pumped larger and larger, huge quadriceps forcing themselves against each other, making Brian have to adjust his stance. His body was held up by huge, impressive calves.
But even more impressive then his calves was his leviathon equipment, which grew along with Brian's muscles. His monster-of-a-dick arched way up into the clouds, miles above the rest of Brian's humongous body. Veins ran up the length of his thick shaft, pumping blood into the erect member, all the way up to the head. The massive mushroom head bobbed up in the air, flaring red and oozing pre-cum. Below his dick were his balls; massive testacles that bounced against his knees. They cleared the landing around his shins while growing, leaving Brian standing in a large, open field for him to enjoy. Brian, finding it harder and harder to touch himself because of his lats, gave his dick a few more strokes before going red in the face and reaching his climax...