I slowly turned the handle and pushed the bathroom door open, thinking I was alone in the house. But as I stepped inside, my eyes widened in surprise. Standing under the warm glow of the bathroom lights was Tina, my girlfriend's 18-year-old daughter.

She was holding onto her towel, trying to cover herself up as quickly as possible. Her long, blonde hair cascaded down her back, framing her petite face. Her thin body still glistening with water droplets from the shower.

For a moment, we just stared at each other, the air thick with an awkward silence. I felt a flush rise to my cheeks as I stood there, wearing just a pair of gym shorts, staring at her petite naked body. Tina's eyes darted around the room, searching for an escape route or a way to hide behind something. But it was too late; I'd already seen everything.

"Uh, sorry," I muttered, stunned at seeing a beautiful naked teenager in my bathroom. "But, what are you doing in my house?" I asked, my eyes running up and down her body.

Tina's gaze snapped back to mine. She shifted nervously under my gaze, her cheeks turning pink as she clutched her towel. "Our water is out and Mom said I could shower over here," she explained, her voice soft and apologetic. "She gave me your spare key and said she told you. I wasn't expecting anyone to be here." Her words were rushed, a hint of anxiety laced within them as she waited for my response.

I nodded slowly, trying to process the situation. "Right, of course. Sorry," I stammered, even though her mother never asked. I hesitated, unsure of what to do next. The tension in the room was palpable as Tina’s towel slipped down a bit exposing one of her breasts. I couldn't help but stare, my eyes fixated on the soft curve and tiny pink nipple. It was as if time stood still in that moment as I struggled to look away, my heart beating faster with each passing second.

She bit her lower lip, glancing down shyly before meeting my gaze again. "It's okay, really. I'm the one who should apologize for startling you like this." Her eyes flickered over my body briefly, a hint of curiosity mixed with the embarrassment in her expression.

I swallowed hard, feeling a familiar stirring in my groin despite my best efforts to ignore it. This was wrong on so many levels. I needed to get out of there before I did something I would regret.

"No worries, Tina. I'll just...uh, take a shower later." I started to back out of the bathroom, bumping into the door behind me.

But Tina took a step forward, her towel shifting a bit to reveal a glimpse of her other tiny breast. "Wait," she said softly, her blue eyes locking onto mine. "You don't have to go. I mean, it’s your house.” She paused a beat, “I don’t mind if you stay.”

Her words trailed off suggestively as she looked up at me through her long lashes and released the hold on her towel. I froze, my mind racing with a thousand inappropriate thoughts. This was dangerous territory.

The towel pooled around Tina's feet, revealing her completely nude body to my stunned gaze. My eyes roamed over her petite breasts, taut stomach, and completely hairless pussy between her slender thighs. She stood there unabashedly, a coy smile playing at the corners of her mouth as she watched my reaction.

"Tina, we can't..." I protested weakly, my voice rough with desire despite myself. "This is so wrong."

She took a step closer, the scent of her floral shampoo filled my nostrils. "I've seen the way you look at me when you think no one notices,” Tina purred, trailing a finger around one of her hardening nipples.

The strength of my determination wavered as I gazed upon her nubile young body. Despite the warning bells in my mind, my eyes continued to roam over her flawless form, taking in every curve and contour. Tina boldly closed the distance between us, her naked figure pressing against mine, her pert nipples grazing my chest and sending shivers down my spine. Rationality was quickly fading as desire clouded my thoughts, making it difficult to resist her advances.

"Tina..." I croaked. "Your mother..."

"Shhh..." she silenced me with a slender finger pressed to my lips. "Mom doesn't have to know. This can be our little secret."

"Fuck..." I groaned, grabbing her tiny waist and pulling her flush against me. She gasped as she felt my hardness through my shorts, a sly grin spreading across her plump lips.

Her fingers deftly untied my shorts, letting them drop to the floor. I stepped out of them, now as naked as she was. Tina's eyes widened with delight as she took in the sight of my fully engorged penis.

"Mmm, impressive," she purred appreciatively, wrapping her small hand around my thick shaft. "Much bigger than the boys at school."

I groaned at her touch, my hips involuntarily bucking into her grasp. She began to stroke me with a firm grip, her pale fingers lightly squeezing my throbbing member.

Emboldened by my response, Tina slowly sank to her knees, never breaking eye contact. Her pink tongue darted out to lick her lips before she wrapped them around the head of my cock. I let out a strangled moan as she took me into her hot little mouth, swirling her tongue around the tip.

"Fuck, Tina," I gasped, burying my hands in her damp blonde locks.

She bobbed her head eagerly, taking me deeper with each movement. I could feel her tongue gliding along the underside of my shaft as she worked me over with youthful enthusiasm. The sight of my girlfriend's naked teenage daughter on her knees, slurping on my dick, was the most erotic thing I'd ever witnessed.

Just as I neared the edge, Tina released me with a wet pop. She rose gracefully to her feet, a mischievous glint in her blue eyes. "Fuck me," Tina breathed, pressing her lithe body against mine once more.

I knew it was wrong, I should just stop with the blowjob, put and end to this madness. But with her perky tits pressed against my chest and my throbbing cock nestled between her thighs, my willpower evaporated. I captured her lips in a searing kiss, my hands roaming over her petite curves, cupping her firm little ass. She moaned into my mouth as I kneaded her cheeks.

Her fingers dug into my shoulders as she ground her hips against me wantonly. I could feel the heat radiating from her bald pussy, tempting me with forbidden delights. Breaking the kiss, I spun her around and bent her over the bathroom vanity.

She gasped in surprise, grasping the sides of the sink as she looked back at me over her shoulder. Her eyes were heavy-lidded with lust, her pink lips parted invitingly. I nudged her legs further apart with my knee, exposing her glistening cunt to my hungry gaze.

"So wet," I growled as I ran my fingers along her slick slit. Tina whimpered and pushed back against my hand, silently begging for more.

Unable to resist any longer, I positioned myself at her entrance and thrust forward, burying myself deep in her womb in one swift motion. We both cried out at the intense sensations as I filled her tight channel completely. Tina's pussy gripped me like a velvet glove, her inner muscles fluttering around my throbbing cock. I paused for a moment, savoring the feeling of being sheathed inside her nubile body.

"Oh god," Tina moaned, her fingers scrabbling for purchase on the smooth vanity top. "You're so big! It feels amazing..."

I smirked at her reaction, pleased that I could elicit such a wanton response from the young temptress. Gripping her slim hips firmly, I began to move, slowly at first, letting her adjust to my girth. But soon I picked up the pace, unable to hold back any longer.

The bathroom filled with the lewd slapping of flesh against flesh and our mutual moans of ecstasy as I drove myself into her over and over. Tina pushed back to meet my thrusts, her pert ass jiggling deliciously with each impact. I looked up into the mirror witnessing the surreal sight of me fucking this young teenage body.

"Yes, yes, harder!" Tina cried, tossing her blonde hair as she threw her head back in rapture. "Fuck me harder! I'm so close..."

I slammed into her sopping cunt with wild abandon. I could feel my own climax building, my balls tightening. A thought flashed through my mind, was she on the pill?

The thought vanished as quickly as it came, lost in the overwhelming sensations engulfing my body. Tina's pussy gripped me like a vise, her muscles fluttering and spasming around my pounding cock. I knew I wouldn't last much longer.

"Fuck, I'm gonna cum!" I grunted through gritted teeth, my hips snapping forward erratically as I chased my impending climax.

"Yes, yes, fill my tight little cunt!" Tina wailed, her voice echoing off the tiled walls. “Fill me with your cum!”

Her filthy words pushed me over the edge. With a hoarse shout, I buried myself and let go, my cock pulsing as I emptied myself deep in her teenage womb. Tina screamed in ecstasy, her pussy clamping down on me as she joined me in blissful oblivion, milking every last drop.

We stayed locked together for a long moment, both struggling to catch our breath. Finally, I reluctantly withdrew, my softening cock slipping free with a wet squish. A rivulet of pearly semen immediately began to seep from Tina's raw, reddened pussy dripping onto the tiled floor.

She turned to face me, a sated, impish smile on her flushed face. "That was incredible," Tina purred, draping her arms around my neck. "I knew you'd fuck me good."

I swallowed hard, reality starting to sink in as the post-orgasmic fog began to clear from my mind. What had I just done? I had fucked my girlfriend's teenage daughter, filling her pussy with my seed. Tina was still smiling up at me, her blue eyes sparkling with mischief and satisfaction, seemingly unconcerned about the potential consequences of our illicit coupling.

"Tina, we shouldn't have done that," I said hoarsely, gently disentangling myself from her embrace. "If your mother ever finds out..."

I couldn't even finish the thought, a cold sense of dread washing over me at the prospect of facing my girlfriend's wrath. There's no way she would understand, no way she would forgive me for defiling her young daughter.

Tina just giggled, completely unperturbed. "Relax. As long as you keep fucking me, I’ll keep your little secret," she said playfully with the undertone of a threat, trailing a finger down my chest.

With that, Tina sauntered towards the bathroom door, completely nude and unconcerned about the trail of cum trickling down her inner thigh. As she reached the opening she turned back and looked at me, “Unless of course I get pregnant."