Wendy quickly decided on a means of concealing Natsu from the world inside her clothing, choosing to keep him in a place where she could continuously feel him moving. That way should wouldn't lose him due to his tiny size.
However, this decision also left her with very few viable options. The least invading of which was to keep Natsu either inside of her shoe or having him hide between her stockings and her thighs. Although Wendy, as a kind-hearted girl, turned both of these options down. Against taking the risk of walking around on top of Natsu, afraid that she might hurt him if he ended up in the wrong spot under her foot.
She needed a soft place, on with sufficient padding to keep him safe from harm. Lacking large breasts to reach this goal, Wendy turned to her third and final option. Quickly pulling up the back of her skirt, Wendy stretched out her panties and dropped Natsu inside. Her face flushed bright red as she felt his tiny body's weight tug on her underwear, rolling down the fabric towards her hill-sized cheeks.
Natsu, taken back completely by Wendy's surprising actions, screamed the entire way down, only silenced when his body slammed into Wendy's rear cheek, her soft skin absorbing the impact and sticking Natuso to her left cheek like a starfish. Thanks in no small part to the layer of sweat that covered Wendy's body from head to toe after their fight earlier.
"Oops. Sorry Natsu, I promise I'll get you out of there as soon as I can. But first, I need to think of a plan for returning you to normal." Wendy added as Natsu peeled himself away from the sweaty Dragon Slayer's backside. Though his efforts quickly turned out to be in vain as she released her panties, allowing them to hit Natsu from behind and trap him against Wendy's bare flesh.
"Weeeeeeeeeendy!" Natsu screamed, his voice muffled through Wendy's well-upholstered fanny. His screams for help quickly silenced as Wendy began her walk back to Magnolia, his underwear prison tightening up and loosening with each subsequent step that the young Dragon Slayer took.
"Huh, did you say something Natsu? I'm sorry, but I can't hear you that well. Please stay quiet until we get back home, you're tickling me." Wendy laughed, her embarrassment beginning to fade.
After a few minutes of walking, Wendy was approaching the front gate to the town of Magnolia. She'd also become quite accustomed to feeling Natsu's movements against her soft flesh, almost finding his struggles somewhat enjoyable. Of course, she'd never admit such a thing to Natsu or anyone else for that matter.
Unfortunately for Nastu, the sweat the had been sticking him to Wendy's ass up to this moment was starting to fade and dissipate, freeing up his body to move more. Of course, this development sounded like a positive turn of events, but at Natsu's size, it was quite the opposite.
First off, Wendy's sweat no long held her panties in place, allowing her butt to chew on them with each step she took heading uphill. Furthermore, Natsu was still too weak to fight against the pull of her cotton undergarments, following them towards Wendy's buttcrack. Her cheeks swallowed more fabric with each step, resulting in a powerful wedgie. And it didn't take long for Wendy to get the wrong idea about what was happening inside of her panties.
"Natsu, just where do you think you're going?" Wendy asks under her breath, only able to focus on the fact that Natsu was getting closer to her petite butthole with each step. Was he doing it on purpose? Sure, she'd gotten used to feeling Natsu against her butt and found it somewhat enjoyable. But she found it hard to believe that Natsu would have felt the same way given his current position. Then she remembered a conversation she had with Carla, where the exceed explained how all men were perverted by nature.
How dare Natsu tries to take advantage of her when she was trying to help him, he was only even back there because Wendy allowed it. His actions tempting the young Sky Maiden to punish him properly, but her gentle nature made it difficult to consider such actions. Maybe she could use her Sky Dragon Healing Magic to try and reverse the effects, would that even work?
While Wendy considered her options, Natsu continued his struggles, only making it easier for his body to slide along the inner curves of Wendy's buttcheek. And given the fact that Natsu wasn't very far from Wendy's buttcrack, to begin with, this served as the perfect catalyst for his body to end up wedged right between her buttcheeks.
Wendy reacted to this by clenching her butt muscles very tightly, her glutes hitting Natsu harder than one of Gajeels iron-based attacks. She stopped dead in her tracks, what could she do now? The Guildhall was still all the way across town, but Fairy Hills was only around the corner. Her choice was clear, heading to her apartment at the member's only hotel. But what will she do with Natsu one she gets there?
1. Wendy forgives Natsu despite thinking he's a pervert now, taking him out of her buttcrack and placing him on the floor in front of her stocking clad feet, using her magic to try and fix what she did to him. However, her magic caused him to shrink in the first place and only intensifies the effects, making him even smaller. Now he's only 1cm tall, less than half an inch.
2. Wendy decides that Natsu must be punished before anything else with a taste of his own medicine. Since he climbed into her buttcrack, Wendy chooses to enact this by forcing him up to her butthole and then pushes him inside for a while.
3. Wendy comes home to find Carla waiting for her, taking Natsu out and placing him between there feet. Explaining everything, including what she believed Natsu was up to. Carla becomes furious and stomps her paw down in front of Natsu, yelling at him and threatening to step on him for Wendy's sake. But when Wendy saves him, Carla insists that Wendy punishes Natsu instead.