When he woke up from his nap he found himself alone in her apartment. It was a bit confusing since they had gone out that morning and she said she wanted to do something with him when they returned. That wasn't a problem so much as the "something" being a complete unknown. At first he assumed she wanted to obtain other somethings for the first something without him knowing, but after a glance and subsequent double-take out the window he realized that she had something else in mind.
For she was enormous, lying down across miles of countryside. She was facing the city and merely observing it in action, looming just beyond its outskirts, hands resting atop breasts like mountains in their own right. From shoulder to shoulder she was probably wider than the city, her hips definitely so, and while "having your head in the clouds" was a well-known idiom she didn't appear to have that problem, not because she wasn't high enough, but because the sheer volume of her warm breath was preventing them from forming.
Leaving the apartment he jogged up the stairs, exiting onto the roof where, against all probability, she looked directly at him, smiled, and waved. "Hi there, sleepyhead."
He glanced to either side in disbelief before cupping his hands to his mouth and shouting, "HOW CAN YOU SEE ME?"
"It's really easy to pick out a main character in a crowd, you know."
"THE SAME GOES FOR YOU, I GUESS," he called back, smiling. "HOW BIG ARE YOU?"
She looked pensive, extending an index finger and holding it vertically as she touched the clearing in the city's park with the tip, comparing its size to the height of the buildings. After a few seconds of mental math she said, "I want say... ten miles?" Her eyes turned back to him. "Care to join me?"
If there was a time in his life where he had disrobed quicker he couldn't remember it, stripping nude on the empty rooftop. Heaving in a breath so large it caused his belly to swell out to the size of an exercise ball, he plunged his thumb into his mouth and blew. There was a rising squeaking and creaking as his cheeks grew larger, each matching the size of his head before every inch of his body surged outward, shooting upwards in height.
Recognizing that his footing on the roof would quickly grow more tenuous, she reached out, gently plucking him up between both fingers. Even with her own massive size he grew quickly in her grasp, forcing her to shift to holding him in her cupped hand as she carefully set him down outside of the city at arm's reach. She pushed herself up to her feet, watching as he rose up mile by mile, meeting her waist, then her chest, then finally eye to eye, cheeks shrinking back to normal as he pulled his thumb from his mouth and exhaled.
"Hi," he said. In sharp contrast to her massively exaggerated hourglass, his figure was more pear-shaped, looking pudgy all over with a very prominent backside and belly. Looking himself over he thought aloud, "I don't know why I end up this way when I'm a giant, though."
She reached out with both hands, giving his gut a shake. "Looks good on you, though. Plus it gives you a lot of cushioning for when I do this."
"Do what?"
She leaped into the air, wrapping her arms around his neck and straddling his belly with her legs. The force sent him tipping backwards, falling to the ground and setting the earth trembling, their collective padding leaving them both unharmed. Pushing herself up with one hand, she reached behind her with the other, aiming his swollen length towards her before sliding down onto it. "That," she replied.
Smiling back at her he reached out, taking her hands in his as she raised herself up before coming back down again. As she did, however, he heard an unmistakable rush of gas and felt his entire body swell and grow again; judging from her reaction, she felt it as well. "Was that- did we just...?"
She nodded. "Yeah." She slowly worked him a few more times, experimentally, and they watched as the world around them grew smaller; his head pressed into mountains that were little more than low ridges, and the blue of the atmosphere in her vision gave way to the dark of space. "Are we...?"
"...pumping each other up with air?"
Their eyes met again and they grinned, going at it with a force that sent tremors out for hundreds of miles. Each thrust pumped the couple bigger, and the bigger they got, the bigger they grew: Twenty miles tall, then fifty, then more, lakes little more than puddles and the city little more than a shapely pebble of stone and metal.
"When do you want to stop?" he breathed.
"Never!"
"Never?" The curve of the planet against his back was becoming more and more noticeable as the seconds passed. "You want to outgrow the universe?"
"Yeah! We'll outgrow everything!" As she came down again onto him, fissures spread across the planet's crust from the force. "We're the main characters of it, after all."
"Alright," he laughed. "Then when there's nothing but us?"
"Then we'll break through the walls of existence itself and find out the truth for outselves!"