As soon as it had begun, the golden moment ended. Steve didn't turn back towards Paul, but he did cast open the shower curtain and step inside. Paul drew closer, noticing that he had to look higher and higher at Steve. The curtain obscured any details, but the bigger man's broad outlines were clear. Soon Paul was sitting on the toilet seat, watching the indistinct front of Steve as water poured down.
Without really noticing, Paul's hand found its way to his cock under the loose clothes. They had been made for someone almost 20% larger than their current wearer so it was no problem to wrap one hand around his boner and stroke slowly, all completely out of view.
Not that Steve could see anything through the shower curtain anyway. But Paul did notice that Steve seemed to be hanging close to the end of the shower where the toilet was. As a result, sitting there was shrinking him faster than anything else all day. Before Steve even got the soap out, Paul was sure he had lost a few more inches.
His eyes were fixed on his giant benefactor as reality seemed to stretch around him. The shower curtain was slowly getting both wider and further away. Millimeter by millimeter, the toilet seat was getting broader beneath him. Even his clothes were rumpling up a little more as he sat there -- the crevasses deeper and the folds containing more material. In fact, the only thing that didn't seem to be changing was the eight-inch erection in his hand. Soon his other hand found its way to his own set of large balls -- some of the largest around, or they had been when he went to work this morning.
Steve seemed to be facing towards him more often, Paul thought as he watched the blurry blob growing behind the curtain. Paul felt himself starting to get close as he watched Steve seem to handle himself, rinsing. Steve had grown a lot during the past 10 minutes, almost a whole foot it seemed. Paul had never seen an eight foot tall man before, and the sight was striking even through the curtain. He realized that he had been doing the shrinking -- more than six inches of it to be sure -- but it was hard to think that way. It just seemed like everything else was getting big.
Unexpectedly, Steve pressed his body close against the shower curtain, putting his dick and balls mere inches from Paul's face. "Hey," Steve said. Paul felt a momentary jolt as his body contracted faster in response, and that was enough to put him over the edge. His dick started to shake and he closed his eyes. "Are you doing OK out there?" Steve asked, but Paul couldn't do anything but groan in response.
Paul heard the shower curtain fly open and the water shut off as his orgasm peaked, and on the way down he managed to open his eyes. His vision was filled with Steve's genitals, as his friend practically stood over him, arms folded. For a moment Steve looked concerned, but then he smiled and backed away. "I guess your dick is doing fine, at least," Steve said, trying to break the tension. "It seems to agree with all this shrinking!" Steve babbled, hoping it was funny.
"Yeah," Paul managed to croak out as his friend's hot body disappeared behind a towel. "I don't know what came over me, but suddenly I was just incredibly horny," he tried to make an excuse. "Sorry," he felt his face flush from embarrassment, but hoped his moustache mostly hid it.
"You do seem a lot smaller now," Steve said. "If you could bottle this, you could replace Viagra over night," he joked. "Of course, it does have a heck of a side-effect. Come on, let's at least get you a clean shirt. Your brother will be here any minute."