He grabbed hold of his dick, Jacking off to it as it continued to pulsate out. He screamed in pleasure as his muscles grew even more, filling his crevices and making his arms shake even more.
He moaned out again pushing himself against the bottom of the tub, rubbing his dick against the surface. He back cracked as the muscles grew even there. While this had been happening his clothes had been torn to shreds, with his dick penetrating through his trousers.
He shook it even more, suddenly he exploded with pleasure. Semen flying out of his dick and doubling in size, the hot tub suddenly cracked upon, To Alex's surpise the water, now filled with his cum spurted out of the hot tub, it went underneath the metal door into the shower room.
Alex cried out as the mixture was drained from the hot tub till it was only him shaking violently with his new massive muscular body and his the slithers of water at the bottom of the tub. Even then he still continued to jack off. Groaning more and more "Oh yes". However he had stopped growing in size due to the lack of that magical water shit.
Alex now slightly pissed stood up for the first time since he had gone in the tub. He was first completely taken aback by his size, He couldn't even stand upright. He flexed his muscles, with hardened his body sending him into another orgasm. After this he walked out of the sauna and looked for where the magical water went.