ever since", she concluded with a slight blush.
He gave her a hug and said, "It seems we're on the same page. It seems so right to me too, and even though neither of us have done it with anyone else to know what it's like to have a boyfriend or girlfriend, it seems to me that we have huge advantages over other young lovers. Like us, I'm sure most of them want to keep their sex life a secret from the parents and that must mean a lot of sneaking around, going out on time consuming dates when they should be studying, and not getting the privacy to do it very often at all, unless it's in the back of a car, or somewhere else that's not as salubrious as the comforts of one's own home and bed. In fact, we have all the advantages of a married couple ... like Mum and Dad, for example. We live together, which teenage lovers can't do in most cases, and are free to make love as often as Mum and Dad do, or more. If they're in the mood, they can't just do it in front of us, any more than we can do it in front of them, but living together as brother and sister, we have lots of opportunities without even having to go out."
"True", she said. "So, right now, while we have the house to ourselves, are you going to make love to me, Robbie?" she asked with a cheeky grin.
"You better believe it", he said with a grin. "Let me hop into your bed for a change", and she folded the covers to one side to invite him in.
As he got into bed with her she started to unbutton her pyjama top and said, "But Robbie, you've still got all your clothes on?"
He rebuttoned the button she had just undone, and said, "When we've not been able to have sex because Mum and Dad are around, I've always found it a real turn on to be cuddling and petting my fully clothed sister, so, if it is all right with you, I'd like to do it that way this time. Besides, it'll be a real advantage if Mum comes home early."
"Oh, yes, Robbie", she said with an excited smile as she slipped down in the bed and pulled the covers over them. "I'd like that too."
They exchanged little butterfly kisses at first, and then Robert kissed his way gently all over her face, including her closed eyes. She moaned as he kissed his way to her ear, nibbled her lobe, and then blew hot breath into her aural canal. He returned to her lips and they kissed passionately as he fondled her beasts through the thick but soft material of her pyjama top. He then ran his hands up and down the softness of her pyjamas, feeling her lithe body underneath - what a turn on! He could feel the intensity of his erection and marvelled at how rapidly it came on, and also at the tenseness of it. It took all his will power not to pull down her pants and enter her right there and then.
She was moaning between kisses and writing under his touch. One of her hands found its way to the bulge in his shorts and she massaged his hardness through the coarse material. He was rock hard and she felt great pleasure and satisfaction in being the cause and focus of his arousal. It made her feel desired and very much wanted, and she wanted him just as badly.
While still kissing her and intensely enjoying the feel of her playing with him, his hand wandered to the crotch of her pyjama pants. He marvelled at the damp heat of her womanhood as he massaged it through the soft material, and traced its lines with his fingers. They were both turned on to the max and devouring each other's mouths like the primal animals they had become.
"Oh, Robbie, take me now or I'll burst", she cried out.
"Delayed gratification, my love", he said, even though he was very much in lust, and of a mind to do exactly as she wished. Instead, he moved down in the bed, under the covers, kicked free the sheets tucked in at the end so his legs could protrude (he was six feet tall and quickly ran out of room), and positioned his head over her mid section.
She watched the bulge under the covers move downwards and found that to be a very erotic sight. Then she braced herself as she felt him tug on her pyjama pants to pull them down just enough to expose her. She gasped as she felt his hot breath on her womanhood, and then cried out and squirmed as she felt the warm wetness of his mouth on her vulva. She held his head between her hands, rolled her own head from side to side, and uttered almost incomprehensible words of encouragement, endearment, and passion, as she felt his tongue exploring her. When she felt his hands under her tiny buttocks, lifting her slightly to bring her hard against his mouth, and then felt him tonguing her clitoris and occasionally sucking all of one or the other labia into his mouth, she spiralled upwards, out of control, tensed in tetanic contraction for a long moment, and then exploded in orgasm, convulsing under him, while vocalising to a degree that made Robert hope the neighbours might not hear.
After twisting, turning, bucking like a bronco, writhing like a snake, and talking gibberish, she eventually started to come down. When she was calm again, other than the occasional, involuntary twitch of her stomach muscles, she said, "Oh, Robbie, that was mind blowing! You are such a good lover. You're turn now."
Robbie said as he reemerged from under the covers, "Roll over."
She obliged and rolled into a face down position. As he sat up, with the covers draped over his shoulders like a cloak, he pulled her pyjama pants down a little further to expose the whole of her cute little bottom and the tops of her thighs. He pushed his hand between her thighs and probed her womanhood, eliciting a sigh from her. He had no need to worry about lubrication - she was hot, wet, and very slippery inside. He released his weapon from his shorts and guided it down the cleft between her thighs and buttocks, found her well lubricated slit, located her vaginal entrance, and after pressing for a long moment against the resistance of her tight love tunnel opening, exacerbated by having her legs bound together but the waistband of her pyjama pants, he felt the obstructing force give way as he popped inside.
"Oh, Robbie, that feels s-o-o-o good", she said, and then grunted or moaned with each thrust.
Robbie found the pressure exerted on his member by her legs-together position to be very exciting and his already high level of arousal started to spiral upwards. Being pinned to the mattress by his weight, and the downwards force of his rampant erection as he pounded her, must have exerted pressure on her clitoris and other erogenous zones because her arousal level skyrocketed under his onslaught. A few minutes later, and after countless pile-driving thrusts, he drove it all the way home, held it in there, cock head pressed hard against her cervix, and arched his back, but while he was holding off for as long as humanly possible, savouring the agony and ecstasy of imminent ejaculation, it was she who cried out in unmistakeable orgasm, clamped down on him, and started to buck under him. This was too much for Robert, and with a lion-like roar he came with explosive force, filling her up with his hot, white, love juices.
When he was spent he collapsed onto her, taking just a little of his weight on his elbows and knees, while still deep inside her. She liked the feel of his weight pressing her into her soft mattress, as she continued to enjoy involuntary twitches, aftershocks, and the feeling of his throbbing dick.
Eventually, his member started to reduce in size, and slid out of her as he rolled over to end up beside her in her bed.
