You look arround and see a giant gray foot print. Sadly, you see your giant sister's foot coming to smoosh you. You thought run away, but she could catch you easy and punish you. Slowly, her sole wrinkles slips over your tiny body, trapping you under a massive feet. Seems that she made it slowly, just for have fun and make you despearte. Your face is being smashed by the bottom of Julie's wide sole.
"There" Julie said as she set her feet in her flip flop and giggles. "So comfy."
Under your sister's feet again, your lips could taste the sweat of her wet sole. If you open your mouth, you could swallow some sweat, but even if you wanted, you couldn't. Julie's soles are smooshing you as she started to walk. The pressure was imensurable and you feel your bones can be break in any moment.
A little 'squeach squealch' sound are make every step. Julie's face are neutral, like you was unware, but in truth, she is pleasured to step on you.
Even in the pain of each step of your giant sister over your poor body, you start to consider: "If I keep resisting, she will keep step on me, to make me suffer or something else. But if start to like her foot... Things can be not so hard to me anymore."

So, under the sweat feet of your giant sister, sandwiched in her flip flop, you will...