Throughout my childhood, my parents never went away on holiday. With my father always working, my older sister and myself were raised mostly by our mother.

We were both grown up now; my sister being 19 and myself being 16, but it was still a great surprise when one Friday night my mother announced that she and my father would be leaving the next morning for a long weekend away. To be honest, I didn’t really care much, but as I could have predicted, my mum said that Tina would be in charge, so I prepared to make myself as scarce as possible for the next three days.

Tina was a nice sister most of the time, but she still seemed to find ways to annoy me. She had long, thick blonde hair and was shorter than me, with a slim and smoothly shaped figure. I was fairly skinny myself, with short dark hair that seemed to style itself every morning, saving me the trouble I guess. Tina had never had a boyfriend as far as I knew; she never discussed relationships much, even when prompted by our mum.

On Saturday with my parents gone, I spent most of the day at a friend’s house, before returning home around mid-afternoon. When I got there however, I was in for a surprise.

As I entered the living room, Tina and another girl I had never seen before were sitting side by side on the couch. I instantly noticed that this other girl was very pretty, with golden girls, a cute face and a low-cut top revealing a large cleavage. She was also a lot taller than both me and my sister, which was noticeable even though she was sitting down.

“Hey Dan, you’re home early”, said Tina with what looked to me to be a nervous smile.

“Hi Tina, who’s your friend?”, I replied sitting down opposite, unable to prevent my eyes from examining this sexy new addition to our living room.

“Well, I’ve been meaning to tell you. This is Kelly, but she’s not my friend”.

“Then what’s she doing here?” I enquired.

Tina hesitated, but Kelly was smiling.

“Well, she’s my girlfriend actually”.

I don’t know what I was expecting, but it certainly wasn’t that. My jaw dropped, and it took me a few seconds to regain my composure and reply. It didn’t bother me; it just came as a surprise.

“Oh well, Hi Kelly, nice to meet you”. I smiled at Kelly, but still couldn’t keep my eyes on her face as they slipped to glance at the top of her large breasts.

“Hi Dan, Tina was just telling me about you”, she grinned.

Tina waited nervously, unsure as to whether I had anything else to say. After about a minute, she broke the silence.

“Right, well…I’ll go and get us something to drink shall I?” She got up and walked out of the room, leaving myself and her girlfriend alone. Kelly looked at me, and I think she noticed me staring at her cleavage. I quickly looked at the floor, but the silence was awkward. Seconds later when I looked up, I got a shock as Kelly now stood over me, face to face. She didn’t look angry, but had a smile on her beautiful face and a twinkle in her eye.

She leaned down over me, putting her mouth next to my ear, giving me the full view of her large tits down her top. I just sat there, stunned as she whispered:

“I saw you looking at me. I know you like what you see. Well I’m staying at your house tonight so make sure you stay awake, I just might pay you a visit.”

She leaned back, chuckled at the stunned look on my face, and returned to where she was sitting on the other couch. Apart from being a virgin, I had never had a girl speak so seductively to me, like that before. I gulped, and noticed that I was hard, though crossed my legs in an attempt to hide it. If she meant what I thought she meant, I could be in for a very interesting night indeed.

The rest of the evening was a strange one for me. Tina had relaxed after telling me, and she and Kelly kept kissing and cuddling just as a heterosexual couple would. Of course I knew all about lesbians and it didn’t bother me, it was just strange to see one of them as my sister, and I had never spent any time with an obvious lesbian couple.

To make things worse, Kelly kept winking at me, pulling down her top to reveal more cleavage and smiling mischievously. I decided to be the first to call it a night (unusual for me) and went up to my room to get some peace. Around half an hour later, I heard Tina and Kelly come upstairs and go into Tina’s room.

Being a hot summer, I usually sleep naked with just one sheet. As I undressed for bed, I remembered what Kelly said, and hesitated. Would she really just walk straight in here? She’d be busy with Tina I thought, but that thought only made me hard again, so I decided to sleep naked anyway and got into bed, listening to the silence.

But there wasn’t silence. My sister’s room was right next to mine, and I could hear noises coming from it. I heard Tina giggle, then Kelly moan in ecstasy. Tina moaned too, louder and I heard the sound of skin slapping together. I presumed that they were having sex, and this went on for at least half an hour, punctuated by the occasional speech:

“Mmm, no, now you lick me now…”.

“Ahh I’m so wet…”

“Put three fingers in Kelly, yeah that’s it babe…”

My imagination ran wild and I couldn’t help but listen to all this intently, even though I knew one of the girls was my sister. It was making me hornier than ever, and my cock made a tent from my bed sheet. If this went on much longer, I would have to make myself cum soon. Before I could get to that though, it had stopped and all was silent again. I listened, but couldn’t hear a sound, yet I couldn’t get the mental pictures of my sister and Kelly all over each other out of my head.

I can’t remember how long it was I had been lying there, listening to the silence and starting to drift off to sleep, when I heard my bedroom door open, and someone stepped in and whispered:

“Hey Dan are you awake? It’s me, Kelly”.

I sat up and bent my knees very quickly to hide my still semi-hard cock, and turned to face the door.

“Yes I’m awake, what do you want?” I replied.

She didn’t answer, but quietly shut the door behind her and then went and sat on the end of my bed in front of me. I still had the sheet covering my knees; it was dark but she appeared to be wearing a dressing gown. I flicked on the light to confirm this. She was red faced and looked quite hot, as if she’d been running. I kept my knees held up to my chest to hide my cock and looked at her.

“What are you doing here Kelly?” I repeated.

She looked at me and smiled.

“Well Tina’s gone to sleep now and I’m not tired. Plus it’s too hot to sleep really. I’m surprised you even need this sheet”.

She yanked the sheet down off the bed, revealing the fact that I was naked, but she still couldn’t see my cock which was pushed up against my stomach by my legs.

“There, that’s better”.

I was still speechless, staring at her. My heart said "fuck her" but my head saiid no. She's your sister’s girlfriend and she’s just had sex with her! I didn’t know what to do, so just sat there. She moved closer, resting one hand on my knee and licked her lips.

“So…did you hear me and Tina next door?”

I nodded, but still didn’t speak.

“I bet you’d like to see what she saw. According to her you’ve never been with a girl before.”

I blushed, my heart jolted and I felt my cock harden yet again.

“But you’re my sister’s girlfriend, surely we shouldn’t…?”

“She’s sound asleep. What she won’t know, won’t hurt her. I’m not a lesbian Dan, I’m bi and I need cock. Not just any cock, I want yours.”

Without warning, she grabbed my feet and pulled my legs out straight, allowing my erect cock to spring free and point skyward as I lay back on my bed. Still with her dressing gown on, she jumped on top of me, the material rubbing against it as we cameH face to face. I felt like this was wrong and I should resist, but I couldn’t. This was what I had been quietly fantasizing about all night.

Kelly was so hot and sexy it almost hypnotized me into staring at her. Then she kissed me on the lips, sliding her tongue into my mouth. I couldn’t help but respond, kissing her back and putting one hand around her. Her tongue was so soft, lively and playful, but it didn’t last long. She pulled away and stood up at the end of the bed, looking down at me and my throbbing cock.

Then she shed her dressing gown, revealing the most sexy sight I could ever wish to see. Her tits were large and perky, nipples erect and with little bite marks around them, presumably from my sister. She was fully shaven, but her pussy still glistened with wetness.

After the night’s events already, I almost came there and then, but just about managed not to.

She leaned down, bending over me, her tits brushing past my cock as she put one hand around it. This wouldn’t last very long, I thought to myself as I tried to hold it back.

I was right. As she began to caress and stroke it, the sight and touch became too much for my virgin body and I came, squirting thick spurts of cum over her hand. She wasted no time in licking it up, moaning softly and even licking it from the tip of my leaking penis. Then she looked up at me, with a rather disappointed look on her face.

“I never even got started!”

“I’m sorry…I just..” I muttered, embarrassed.

“Am I really that hot Dan?” She smiled playfully.

“Uh yeah you are”, I replied, also attempting to smile but still blushing.

She got up, stepped back and picked up her dressing gown, wrapping it around that incredible sexy body, hiding it from view. I was relieved to see that she was still smiling. She walked past my bed, stopped to lean down and kiss me briefly on the lips again. I savored her soft and delicate touch.

“I’ll be back for more, so be ready…” she whispered into my ear.

And with that, she flicked off the light and left the room, leaving me in an amazed silence. Lying on my back with my cock falling, my imagination wasn’t big enough to wonder what would come next.