Rimuru had assumed that being in Shion’s dress shoe at this size would be challenging, but he vastly underestimated just how difficult things could get. Out of nowhere, Rimuru was lifted in the air with her foot, before it hurtled back down to the ground. Each time her foot made contact with the ground, he felt he was being smashed by a meteor, and the rising and falling just kept repeating over and over again. The crashes were deafening too, and the longer it went on, the more Shion would sweat. Whatever started had only just begun, but for Rimuru, it was entirely too much.

There were a few moments where the impacts were severe enough to cause pain, leading Rimuru to switch to his slime form. That created other complications, since he was forced to slide all along her sock, from her heel to her toes. It was then there that he felt like Shion's sweat, unable to change back due to the ever present fear of being smashed to bits under her foot.

Then out of nowhere, Shion stopped, giving Rimuru a much needed break from being crushed underfoot. After that, he heard the voices of Hakuro and Gobuta. Hakuro was a kijin and a master swordsman, and Gobuta was a young but talented Goblin warrior.

“Ah... Shion! I see you are working hard.”

When Shion heard Hakuro’s voice, she spun around, practically drilling the tiny slime under the ball of her foot. She then smiled and said:
“Hakuro! I’m in the middle of my daily training! I need to remain useful for Lord Rimuru...”

Rimuru would have rather been removed from Shion’s shoe, but he wasn’t in a position to make requests to Shion right now. Though while standing still, it wasn’t nearly as bad, though the pressure was still fairly tough for him to manage without his resistance skills. While waiting for a response, Shion absentmindedly twisted her shoe into the dirt, brutally grinding Rimuru with the ball of her foot. If he weren't currently in his slime form, that would have been seriously painful, though being so thoroughly pressed into her sock felt incredibly demeaning to him.

“Hey gramps, can we take a break now?”

When Gobuta said that, Hakuro silently unsheathed his blade before saying in a menacing tone:

“I think we should ramp up your training instead...”

While Gobuta ran away screaming, Rimuru could only sigh, wondering when the young Goblin would learn how to filter the things he said. He didn’t have long to muse on that, since Shion immediately stomped her foot, shocking Rimuru from the loud and sudden impact. After doing that, she took a deep breath and said:
“I need to keep working hard for Lord Rimuru too...”

She then resumed her run, forcing Rimuru to continue sliding along her sock in slime form, unable to stop himself. Since he was barely any bigger than any other bead of sweat, Shion hadn’t the slightest suspicion that she was putting him through such a humiliating experience. She just continued to run, motivated that she could have her great Rimuru so close while she trained.

At one point though, Rimuru slid back to her toes, and got forced into a small tear in her sock. Due to that, he slid all across her sweaty bare skin, where her sock was just tight enough to prevent him from changing back to his human form. Her sole was incredibly smooth and warm, making Rimuru feel like he was a tiny sweat rag, especially whenever he was forced into the small but numerous cracks and wrinkles along her skin. If he weren't currently in his slime form, being forced into those tiny spaces would likely feel uncomfortable. Though due to his natural ablities that weren't surpressed, he was forced to absorb all of the dirt, sweat, and dead skin that formed along Shion's foot. It was a good thing that he had plenty of storage space to spare, because he couldn't stop taking in that filth if he tried. And her heel was both rough and somewhat calloused, but since he was in his slime form, that didn't bother him very much.

After about half an hour, he crashed into the side of her 2nd toe, which was more than twice his size. And due to that, he clung to her skin with the rest of her sweat, unable to free himself. When he switched back to human form, he still couldn't free himself, no matter what he tried. But while in his human form, he was forced to taste Shion's sweat, due to it practically raining down around him.

"Ugh... Maybe it's an acquired taste...? But I can't wait until this is over..."

After Rimuru muttered that, he wiped his mouth, though he guessed that he'd be ingesting plenty of Shion's sweat before the day was done. However, one particularly powerful footstep sent Rimuru into the space between her 2nd and 3rd toes, where her sweat acted like an adhesive. Before he could even attempt to free himself, Shion stopped and clenched her toes, smothering Rimuru with her sweaty flesh. As the seconds crawled by, Shion squeezed her toes harder and harder, nearly suffocating him. At the very least, she was reminding Rimuru that she was one of his strongest officers.

"That was good... Now to work on my sword swings!"

Following that statement, Shion started to walk back to the training area, unknowingly battering her tiny master with each and every step...

Due to just how actively Shion trained, all Rimuru could think about was survival. In a way, being crammed between her toes was a lot better than any other location in her sock, since he wasn't being crushed under her monolithic weight at least. But she made up for it by frequently scrunching and wiggling them, treating her tiny master more like a toy than anything else.

All throughout that, Shion sweated profusely, working twice as hard as usual since she thought that Rimuru was closely watching her. Instead, he was under constant threat of drowning, which felt odd since he was a slime and technically couldn't drown. But shifting to his slime form would be much too risky, lest he receive another full tour of Shion's foot.

After half an hour, Rimuru was feeling light headed, when he heard Great Sage announce:

'Warning: Vitality levels low. Entering forced recovery sleep.'

Rimuru's body slowly melted back to his slime form, much to his disapproval. He was the one that their entire nation was centered around, but right now he was nothing more than another droplet of Shion's foot sweat. Even if he didn't hate the experience, it was a heavy hit to his ego.

"That was perfect! Let's relax in the baths next, Lord Rimuru!"

Shion's enthused, yet strained, declaration was the last thing Rimuru heard before losing consciousness...