Teaching Nerdy Little Step Sister About Sex

I never thought my nerdy little step-sister, Mia, with her thick glasses, messy ponytail, and oversized comic book tees, would ever ask me about sex. She's 18 now, buried in her room studying physics or bingeing anime, but one night she knocks on my door, cheeks flushed pink. "Bro, I... I don't get it. All my friends talk about it, but the books make it sound so clinical. Can you... teach me?" My cock twitches instantly. She's innocent, untouched, her perky B-cups straining against that tight My Little Pony shirt, her short plaid skirt riding up her creamy thighs. I pull her inside, lock the door. "Sure, Mia. Lesson one: touching." I guide her small hand to my bulge, feeling her tremble as she squeezes my hardening shaft through my boxers. "Feel how big it gets for you?" She gasps, eyes wide behind those nerdy frames. I strip her slowly, peeling off her shirt to reveal pale skin and stiff little nipples begging to be sucked. My mouth latches on, tongue swirling as she moans like a virgin geek in heat. "Oh god, bro, that feels... electric!" Her panties are soaked already, a wet spot blooming as I slide my fingers under the fabric, parting her slick, shaved pussy lips. She's dripping, so tight my finger barely fits, but I pump it in, curling to hit her G-spot while she bucks against my hand. "Lesson two: taste." I push her to her knees, freeing my thick 8-inch cock. Her lips part hesitantly, but once I feed her the head, she sucks like it's her new favorite lollipop, gagging cutely as I face-fuck her virgin mouth. Drool runs down her chin, mixing with tears of overwhelmed pleasure. I can't wait anymore. I bend her over my desk, surrounded by her sci-fi novels, and yank her panties aside. "This is how it feels to be fucked, sis." My cockhead nudges her entrance, then slams in balls-deep. She's so fucking tight, clenching like a vice, her nerdy whimpers turning to screams: "Harder, teach me everything!" I pound her relentlessly, ass cheeks rippling, her glasses fogging up as she cums hard, squirting all over my thighs. We go all night—doggy on her bed, her riding me reverse cowgirl while reading porn aloud in that squeaky voice, even anal when she begs for "advanced lessons." By dawn, my little step-sis is a cum-drenched slut, glasses askew, begging for daily tutorials. Who's the nerd now?