You hack as your mouth and nose are forced directly onto the insole of the worn trainer. You're shaking, still deeply unnerved by your visceral reaction to the taste of your sister's ratty shoe. Amy is cackling maniacally, the sound sending shivers up your spine. You don't think you've ever heard her this thoroughly amused by you since the first time she made you lick her feet...
---
She had just come back from one of her lengthy soccer games and bounded up to your room, only taking off her cleats just before she entered the house. Much like what's happening now, she slammed her footwear directly onto your nose, giving you no reprieve from the sweaty results of the intense dedication she had for her team. After a few minutes of sniffing up her muggy cleats, she wrapped her socks around your nose, then shoved her toes into your gasping mouth. You were overwhelmed by the ungodly flavor of overworked feet and a flood of sweat, both recent and old, ravaging your tongue. Your mind couldn't even process the thought to fight back; you simply accepted the wiggling digits, their rhythmic pushing and pulling inadvertently causing you to suck, coaxing your body to work against your dignity. It was practically a complete admission of your inferiority to her. Ever since that day, she became even more obsessed with having you at her rancid peds, leading to the hopeless situation you're in now.
---
Amy wraps an arm around you from behind and brings her mouth to your left ear. "Enjoying yourself, huh, lil' bro?
Snapping back to reality from your traumatic flashback, you realize you had never stopped dragging your tongue up the disgusting insole of your sister's trainer. The filthy, salty material stains your mouth, and you actually feel some dried sweat being scraped off the surface, infecting your taste buds, then pumping down your throat, becoming part of you. You can't explain it, but there's something...different about it this time. Your pulse is racing, and you haven't stopped shaking since you moaned out loud.
Suddenly, a soft, perfectly pedicured hand shoots down your pants, through the waistband of your trousers, and squeezes your bare dick. Your breath hitches in your throat, not just because of the unexpected stimulation of your member, but because...you're already rock hard!
The hand begins to jerk you off, flooding your brain with endorphins like how the ratty, humid shoe you held against your face flooded your olfactory senses with the bitter taste and reek of a 3-year-old shoe and the familiar, stinging aroma of its hot, humid, smelly passenger. You groan, the desire in its cadence clear as crystal to anyone within hearing range.
"Hahaha...heeheeheehee," Amy continues to giggle like mad, ecstatic to hear your true, primal thoughts about her feet that your body was letting spill out. "So you finally admit it, Stan? You admit that your rightful place is life is under me?" You're glad you can't see your sister's face; you're sweating bullets, and the thought of even looking yourself in the mirror after this utterly pathetic display is almost too much to bear.
"I want to hear you say it, bro~" Amy whispers into your ear, her hot breath sending goosebumps through your skin. You feel the hand tracing your chest leave its position, taking the trainer from your hands and giving you room to breathe. "What are you?"
"I-I-I--" you stutter, the revelation pressing down on your skull like a giant's hand, threatening to crush it into a pulp. No, you're not doing this, t-this is u-u-unthinkable...
She slows her pace down to a halt, tightening your shaft into a death grip, intent on forcing your admission out of you. She whispers one last time.
"Don't tell me that awful lie you repeat to yourself, bro. Tell me what you really are..."
The pressure in your balls is too much for you to handle. Your mind is on autopilot. You let go, not caring about the consequences, and answer the question, not only for your sister, but for yourself, too.
"I-I'm...I-I'M..."
"I'M YOUR PATHETIC FOOTSLUT--!!!"
The trainer clamps back onto your face, and you take a deep, willing inhale. The rank, cheesy stench of your sister's sexy feet flows into your lungs, and permanently alters your brain chemistry. You let out a loud, unrestrained moan, releasing years of sexual frustration that built up to this moment, and cum. Amy speeds up her pace, keeping her firm grasp on your cock as she milks out ages of unnecessary stress, washing your mind with bliss unrivaled by any other high in your life. The sticky ropes keep on coming, practically soaking your entire pant leg. All the while, your sister pulls your body even closer to hers, wrapping you in her strong, comfortable embrace. A sense of all-encompassing relief soaks into your very bones; a huge, unbearable weight had been lifted off your shoulders.
"Finally..." Amy sighs, a blissful smile on her face as your body goes limp. It had taken years of calculated prodding and torture, but she had finally gotten you to admit your inferiority, and unlike every other time she had you say it, she could tell that you really meant it.