Greg finally tore his eyes away from Mark's butt.
"I don't want to be the Guinea pig anymore," he said. "You take one."
"We're trying to find something to fix you," Mark said, furrowing his brow. He gestured to Greg's fat, naked body for emphasis.
"I know, and we ARE going to," Greg said, glaring back. "But fair is fair. You need to drink one, too."
Mark sighed. He didn't want his body to get screwed up by the wrong vial. But he did have a point.
"Which one?" he asked cautiously. Greg scanned the rack for the perfect vial. He reached for one, then changed his mind at the last moment and handed Mark another one.
Mark looked at it. It was the sawtooth-outlined one. At least it was human. He drank it too quickly and choked for a second. The oddly smoky flavor lingered in his mouth. He replaced the vial just as an otherwordly itch overtook him. Without thinking, he tore the bathrobe off, leaving him as exposed as Greg. He scratched at his skin vigorously, but the itch only got worse.
Relief struck him as Greg reached out and scratched his back for him. He sighed in relief and scratched out the rest of the itches. He caught a glimpse of movement below him. He looked down to see his chest hair moving ever so slightly. Startled, he scratched at it, but there wasn't anything in it. Upon closer inspection, he saw that the hair itself was growing longer and thicker. His chest hair was already thick from the double dose of the Male Vial, but under the effects of this new vial, it became so thick that he couldn't even see the skin under it. He felt movement on his arms, legs, and face. Hair wasn't meant to move, and his nerves thought that something was moving on his skin. He patted at them as the hair on them thickened.
Greg was still scratching his back, and he felt the faint movement of back hair appearing as he scratched. It didn't seem to be as thick as his chest hair or belly hair, though. Hair completely covered his arms, in places he didn't even know hair could grow, like the inside of his forearm. It was all a little gross, actually, but it was hardly the worst vial Greg could have chosen for him. He turned his head and felt a scratch on his chest. He reached up to find that his neatly trimmed goatee was gone, replaced with an enormous, bushy beard that grew down to the top of his chest. Oddly, the hair on his scalp seemed unaffected. It retained the short spike cut that he'd had from the first vial he'd tried.
He sighed. All that work he'd put into shaping his beard was undone with just one vial. He decided to leave it thick and bushy, at least for right now. No need for wasted effort.
"There, happy now?" Mark said, a little bitter. Greg didn't have to answer. His erection was answer enough.
"Anyway, it's your turn now," he said, turning back to the rack of vials.