It had been a very nice fuck, her parents had gone out for the day so Sally and I could be alone. We lay naked on her big bed and I gently kissed her nice big tits. They were one of the things that attracted me to her in the first place, true she was very pretty with great legs but it was those tits thrusting proudly out from her tight top that stop me dead in my tracks. About an hour ago the front door slapped and both Sally and I jumped a least foot in the air.

"It's only me," shouted Pam.

She was Sally's younger sister and I had also noted in passing that she had some great tits too. Once the shock had passed we settled down for a second steamy session.

"Don't mind me, guys," said Pam as she walked unannounced into her sister's bedroom.

My first reaction was dive under the covers and hide but when I spied Pam I stopped and just stared.

"What are you doing?" said an incredulous Sally.

I could see what she meant, for Pan was just wearing a pair of very tight jeans leaving her superb thrusting tits bare.

"Sorry, but I need to use your big mirror urgently," she explained. "I promised Bill to e-mail him a pic of my tits."

"What!" shouted Sally.

"I won't be a minute so keep your shirt on," said Pam who posed in front of the hanging mirror and raised her cell phone.

"Well, it pretty obvious that you didn't keep your shirt on," snapped Sally.

I watched, opened mouthed, as Pam folded one forearm under her magnificent bust to raise them slightly before snapping off a couple of pictures with the built-in camera in her cell phone.

"There you go, all done," she laughed. "Now you can get back to your bonking."

The door closed behind her leaving us stunned and silent.

"I'm going for a shower," grumped Sally whose lustful mood was broken.

I just sat there staring at the closed door, still seeing those magnificent tits in my mind. Sally isn't small by any means, I think she's at least a 'C' cup but she hasn't said. Pam must be at least a cup size bigger if not two; to add to their size there stood straight out from her chest with hardly any droop.

After that, every time I saw Pam my eyes would zero on to her bust and of course she would notice and she would smile knowingly at me. One Saturday afternoon I was waiting for Sally to finish dressing so we could go out when Pam came into the lounge.

"Hiya," she said.

As usual, my eyes fixed on her thrusting tits.

"I'll bet you would like to get your hot hands on them," she said with a giggle.

"W-what!" I stuttered?

"Come on now, just say it," she giggled again.

She moved closer and eventually sat down on my lap, her legs astride me.

"Please," I begged, "Sally is just upstairs."

I don't want to think about what Sally would do to me if she saw her sister sitting on my lap.

"You know you want to," she said ignoring my words about her sister. "Here, give me your hand."

I should have stopped her but I let her pick up my right hand and she placed on her left tit.

"Have a squeeze," she giggled. "Devine, isn't it?"

She wasn't wrong there.

"Use both hands," she instructed.

God, if Sally saw this I would have my dick cut off for sure. My hands were just getting used to their feel and weight when we heard footsteps on the stairs.

"Right, I'm done," said Sally. "Oh, hi Pammy."

Pam was sitting on the sofa a good ten feet away from me, she had covered that distance in just a second. Pam didn't say anything just waved an arm at her sister. My hands were still tingling from the touch of those tits as we drove away.

I had my own place, just a small one bedroom flat but it was mine. My mobile phone beeped and it told me I had an incoming e-mail. There on the small screen was the very picture that Pam took in her sister's bedroom, her tits all nice and bare. Under which the message said.

'If you want some more of these, open your front door'

I almost tripped over nearly breaking my neck getting to the front door.

"Hi," smiled Pam.

She walked past me into my small flat.

"My mail got your attention then?" she giggled.

"Yeah," I said with a lustful smile.

Today, she was wearing a short skirt and a button up top.

"I hope you've got some condoms," she said off hand. "I hate getting messy. Once, these two guys spurted all over my face, bloody disgusting."

While she was talking her hands were busy stripping off her few clothes.

"Right, I'm hot, ready and willing," she giggled standing naked in my lounge. "How about you?"

My cock was painfully hard in my pants so I quickly stripped off too.

"My, my," she said her hand moving over my stiff member. "You've got a nice big one."

In truth, it was only seven inches but today it felt twice as big.

"Come on, you know you want to get your hot hands on these again," she said pushing her chest out towards me.

They felt even better naked, full and firm.

"That right, stud," she groaned, "Squeeze them for me."

The carpet was thick and comfortable as we lay down in the centre of the room.

"Come on, be quick," she said her legs opening wide to receive me.

I rolled on the condom and then pushed deep inside her; her hips pushed against me as we moved together. This wasn't going to last long at the pace we were going.

"Harder," she grunted her hips jerking.

I couldn't hold on any longer so I let go and pumped my spunk into the condom. Under me her hips jerked twice more then she squealed and then she too became still.

"Mmm, that was super," she sighed.

Just as soon as I pulled out and rolled off her, my conscious kicked in.

"Don't worry about Sally," she chucked as if she had read my mind. "I wouldn't tell her anything."