Just as the Kris's transformation began to kick in, daylight broke through the clouds. "Noo!" he screamed at the obscured moon. "Not yet! Fuck!" He felt his still-human body body shrink, but only slightly.
Meanwhile, Nate began his own reversion, as his fur and limbs thinned. He writhed on the ground, tongue lolling from his mouth as his snout retreated into his face. Kris watched as his brother's still erect cock mostly retreated into its sheath, which detached from his belly. The red cock-tip faded and widened into a pink mushroom, and the surrounding pubic fur curled back into pubic hair. His tail shrank into a sliver before disappearing above his hairy buttocks. Now human, Nate sat up, coming to his senses.
"Why am I naked? And what happened to your shirt and shoes?"
Kris shrugged. "We went swimming in the pond."
"Oh." He squinted at Kris in the morning light. "You...look different."
"Really?!" Kris ran to the pond and looked at his reflection. It was true! He looked older! Bigger! Manlier!
His body must have needed to go through accelerated puberty before it could transform further. Though daylight broke in time to prevent him from changing species, he still retained a more mature body. Now he would just have to wait for the next full moon...
Nate joined his brother by the pond. "Yeah, you DO look different," he said, frowning slightly.
Kris shrugged again. "Just a growth spurt. And YOU look different too."
Nate gazed at his reflection and saw that Kris was right. His chest hair, which had grown after his first transformation, was now like a carpet, leaving visible only the tips of his nipples. His ears were pointed and his eyes had lightened to almost yellow. Super-thick stubble ringed his mouth, which opened to reveal unusually-long canines. He was few inches taller--and his cock was a few inches longer. Witnessing all these changes started making him somewhat excited as well...
Kris smirked and pointed. "I think you've got morning wood bro."
Nate looked around and saw no one else in the park.
"I gotta take care of this" he said, as one hand began massaging his cock.
"I'll keep you company" said Kris, who dropped his shorts and began wanking too. He was excited to see that his own cock and balls had grown, the former by at least two inches. It was also darker and veinier.
The two brothers stood side by side, masturbating in the early morning sun. As Nate neared climax, Kris put his free hand on his brother's cock to help. Nate reciprocated, and soon, arms interlinked, they shot an enormous pile of semen into the grass by the water's edge.
"Oh God, that felt so good," moaned Nate. "Thanks for helping bro."
"Anytime. But I think you'd better find your shorts so we can go home."
As Nate did so, Kris quickly knelt down, scooped up a handful of cum, and licked it up like honey. He wanted all the transformation juice he could get.