Jon's human sized penis wasn't fully erect yet. He had a few seconds to think "Oh, shit! I dropped the stone!" Then he felt it pulsate, growing larger, and larger. It had hit six feet just before it stopped, the arousal was amazing. He could feel every inch of flesh upon it.
His balls had grown from his former legs, swelling in size until they were as big as car tires. He couldn't think at all, all he could do was rub and rub, trying to stimulate his massive member. Then he cam, a load so big it oozed onto the floor, two gallons of cum at least. He tried to think but it went hard again. He was stuck in an eternal cycle now.
