Not Her Master Any Longer

When you had lost your final duel and had been banished to the Shadow Realm you had listed in lonely despair at first, before realising that the single card that had been left in your hand had come with you. You thanked the gods above that it had been a monster card, and the most sociable one in your deck at that. Comforted somewhat of your grim fate with the prospect of companionship you eagerly summoned Dark Magician Girl, who looked around confused at the strange environment they found themselves in. You explained your circumstances to her and how you were hoping she would keep you company in this empty void, and while somewhat frazzled by her unfamiliar task she had smiled gently and abided by your wish. For a few weeks you had tried to make conversation with her, but she really had little to say and your relationship soon turned to you simply monologuing to her while she lazed nearby in silence. You would reminisce about your life on earth, the duels you and her had fought in the past as well as general moaning about having ended up here. Perhaps you were to caught up in your woes to pay much attention to her, or perhaps she was good at maintaining a patient façade, regardless you had not noticed any warning signs about her before she suddenly snapped. You were cutoff midsentence one day by a blinding flash of magic coming from her direction, when you're vision returned you had suddenly been enveloped in a massive mass of cloth. You're struggles against it were pointless but it was soon thrown off of you regardless, and you were greeted by the sight of your now titanic companion glowering down at you. A quick glance to the side showed that the cloth mound had actually been you're own clothes which were now drifting into the void, but you were too confused and nervous to care much for your nudity as you looked up at the irate giantess. 
"I just couldn't stand listening to your whining voice any longer! I know you're supposed to be my master but it's not like we'll ever get to duel again, and with how badly you lost your last one I don't think you deserve to have me serving you any longer! I thought about just blasting you to dust with my magic but I felt like one of your gripes at least was reasonable, being stuck here alone for all eternity would be far too boring. You've already blown your chance at conversation though so I decided to just keep you as a toy, which your new size is far more fitting for wouldn't you agree?"

You frantically tried to plead to the fed-up goddess for mercy but she either couldn't hear or ignored you, instead idly waving her hand and summoning a translucent platform beneath both of you which caused you both to land, the magical platform apparently had it's own gravity. You hit the ground with a painful thud and before you could gain your bearings a giant shadow cast over you, you caught a brief glimpse of the ratty sole of her expansive boot before it slammed down on you like a meteor. The pain was immense but you bizarrely weren't dead, despite feeling stretched out and flattened beneath her grimy tread. You assumed she had cast some sort of protection spell on you to keep you from breaking as she "played" but your giantess spoke nothing to confirm that, silently entertaining herself by stomping and grinding you against the ground for what felt like days. Seemingly satisfied with her game at last she peeled you're splattered form of her boots with her delicate fingers, and let you reform over the next few minutes in her palm. Unbeknownst to you she had kicked off one of her boots in the meantime and after confirming you were fully healed she used her magic to fling you into the depths of it, you landed with a disgusting squelch on her well-worn insole. Her foot slowly entered and chased after you as you crawled backwards in fear, finally pinning you with ease as you both reached the toe section of the boot. As you tried to struggle in vain against the crushing weight your new owner's voice suddenly rang through your head, ordering you on what she expected you to do in here. 

"I won't be providing you food and drink any longer so I recommend you get used to the taste of my sweat and foot grime, I expect you to lap it up even when you aren't hungry. If you don't pamper your goddess properly she will be forced to punish you, and I promise that will be far worse than the harmless playing we've done so far."

Frightened of what could be done to you if this sadistic giantess actually put her mind to it you nervously obeyed her commands, gagging down on the rank byproducts of her sweaty foot. Anytime you paused for too long her nearby toes would squeeze you in their slimy embrace until you felt you might pop, and your goddess would issue a cold warning to resume your task. As awful as your new role of living insole was you were even more frightened by the future, time didn't pass in the Shadow Realm and your giantess had the magic to keep you alive no matter what torment she cooked up for you. An eternity of being this cruel girl's plaything unnerved you to your core as you thought of it but you knew you had no chance to escape, you could only pray that you would grow to love it in time...