Playing Dirty With My Brother’s Girlfriend

The summer heat clung to everything like a second skin, and our old family cabin by Lake Wisteria was no exception. My brother, Jake, had brought his new girlfriend, Mia, for a weekend getaway. I’d tagged along to fish, grill, and maybe mess with Jake a bit—classic younger brother stuff. But the moment I saw Mia step out of the car, her sundress hugging her curves, I knew this trip was going to be trouble. She had a big, round ass that swayed with every step, and her confidence made it impossible to look away.

Jake was oblivious, hauling coolers and fishing gear while Mia and I exchanged small talk. “Nice place,” she said, her voice low and teasing as she surveyed the rustic cabin. Her dark eyes flicked to me, lingering just a second too long. “You come here often, Ryan?”

“Only when I need to remind Jake he’s not the only one who can catch a fish,” I shot back, grinning. She laughed, and something about the way her lips curled made my stomach tighten.

The first day was tame—barbecue, beers, and Jake droning on about his new job. Mia and I kept stealing glances, though. By the second night, Jake had passed out early, snoring on the couch after one too many IPAs. Mia and I were still up, sitting on the porch, the lake lapping softly in the distance. The air was thick with humidity and something else—tension.

“You’re the rebellious one, aren’t you?” she said, sipping her wine, her bare legs stretched out on the wicker chair. Her dress rode up just enough to show the curve of her thigh.

“Me? Nah, I’m the good brother,” I said, leaning back, trying to play it cool. But my eyes kept drifting to her body, the way her chest strained against the fabric of her dress. She caught me looking and didn’t flinch.

“Good brothers don’t stare like that,” she teased, setting her glass down. “But I don’t mind.”

My heart kicked up a gear. “Careful, Mia. Jake’s right inside.”

She smirked, leaning closer. “Jake’s out cold. And I’m bored.” Her voice dropped, husky and deliberate. “You gonna entertain me, Ryan?”

I should’ve shut it down right there. But the way she looked at me, the way her big ass shifted as she stood and walked toward the cabin, beckoned me to follow. I did, like a moth to a flame.

Inside, the dim glow of a single lamp lit the living room. Jake was still snoring, oblivious. Mia grabbed my hand and pulled me toward the back hallway, her fingers warm and firm. “Quiet,” she whispered, leading me to the guest bedroom.

The door clicked shut, and she was on me, her lips crashing into mine. Her kiss was hungry, her tongue flicking against mine as she pressed her body close. I could feel every curve—her full breasts, her hips, that incredible ass I’d been sneaking glances at all weekend. My hands roamed, grabbing her backside, squeezing the soft, firm flesh through her dress.

“God, you’ve got an ass,” I muttered against her lips, my voice rough.

She pulled back, grinning wickedly. “You like it? Show me how much.”

She turned, bending slightly, her dress riding up to reveal lacy black panties. My hands were on her in seconds, sliding the fabric down her thighs. I knelt behind her, kissing the smooth skin of her lower back, my fingers digging into her hips. She moaned softly, pushing back against me.

“Fuck, Ryan,” she whispered, her voice thick with need. “You’re bad.”

“You have no idea,” I growled, standing and turning her to face me. I tugged her dress over her head, revealing her bare breasts, full and perfect. My mouth found them, kissing and sucking, her nipples hardening under my tongue. She gasped, her hands threading through my hair, pulling me closer.

“More,” she demanded, her voice low and urgent. “I want you to fuck my tits.”

The words hit me like a freight train. I pushed her gently onto the bed, straddling her waist as she pressed her breasts together, creating a perfect valley. I slid my cock between them, the warmth and softness driving me wild. She watched me, her eyes dark with lust, her lips parted as she moaned softly.

“Like that?” she teased, her fingers grazing my thighs. “You’re so fucking hard.”

I groaned, my hips moving faster, the sight of her beneath me almost too much. But I wanted more—needed more. I pulled back, my hands finding her hips again. “Turn around,” I said, my voice rough with desire.

She obeyed, getting on all fours, her big ass raised high. I ran my hands over her curves, my fingers teasing her entrance before sliding lower. “You ever…?” I started, my thumb brushing against her tightest hole.

She glanced back, a wicked smile on her face. “Only if you’re good at it.”

I grabbed the lube from my bag—yeah, I’d packed it, just in case—and slicked my fingers, working her slowly, carefully. She moaned, her body relaxing into my touch, her hips rocking back. “Fuck, that’s good,” she gasped, her voice muffled against the pillow.

I took my time, easing her into it, my fingers stretching her gently until she was begging for more. “Please, Ryan,” she whimpered, her voice raw. “I need you.”

I positioned myself behind her, sliding in slowly, the tightness almost overwhelming. She gasped, her hands gripping the sheets as I moved, steady and deep. The rhythm built, her moans growing louder, more desperate. “Harder,” she pleaded, her voice breaking. “Fuck me harder.”

I gave her what she wanted, my hands gripping her hips, my thrusts deep and relentless. Her big ass bounced with every movement, the sight pushing me closer to the edge. She reached back, her fingers circling her clit, her moans turning to cries as her body tensed.

“Ryan, I’m gonna—” Her words cut off as she came, her body shuddering, clenching around me. The sensation was too much, and I followed, my own release hitting hard, leaving me breathless.

We collapsed onto the bed, panting, the air heavy with the scent of sex. She turned to me, her eyes still smoldering. “You’re definitely trouble,” she said, a lazy smile on her lips.

“And you’re fucking dangerous,” I shot back, still catching my breath.

She laughed softly, then glanced toward the door. “We should get back before Jake wakes up.”

I nodded, but as we dressed, the reality of what we’d done settled in. Guilt twisted in my gut, but so did the thrill. Mia caught my eye, her expression unreadable. “This stays between us,” she said, her voice firm but soft.

“Deal,” I said, knowing I’d never forget the way she felt, the way she moved, the way she’d pushed me to the edge and beyond.

As we slipped back into the living room, Jake still snoring, I couldn’t shake the feeling that this wasn’t the last time Mia and I would play dirty. And part of me—a big part—hoped it wasn’t.