The Living area should be empty this late at night.

It was ironic that the large, open sitting room, dining space and kitchen with it's sliding patio doors and (when it was light outside) clear view of the loungers, the table, Dad's netted or mesh hammock (his pride and joy) and the pool with it's showerhead on the wall. Right now however there was only the reflection of yourself on those distant black doors, wearing just a t-shirt that just covered your dick when flaccid, but with your current erection hid nothing.

Trying to admire yourself for a minute in just the half-light of the many softly beeping gadgets in the room and the light spilling downstairs from the open bathroom upstairs, who's warm yellow light came down enough to illuminate basically only you in the whole space. Peeling off your shirt with one hand, you run your fingers around the foreskin of your hard cock with the other. There's the wetness of precum there already, and the sensation makes your finger tingle.

Standing naked in the house feels as amazing as ever, but riskier by far than exposing yourself at Sara's.

You spread out on the couch, and find some porn to watch. Feeling especially perverse, you think of Lucy stretching and basically doing yoga here in her leggings. She did it most days while watching tv or an audiobook, or sometimes when Charlie was brave enough to practise her percussion or guitar excercises, and on the rarest days, a complete piece.

Lucy would contort herself into sensible and straightforward poses, but it was still alluring, now that you thought of her doing it while you stroke yourself. Watching a film about a swingers resort where a group of siblings don't tell the other guests that they're closely related. Your pace is slow as the movie begins, with the sound on low, you can stay here all night. The siblings trouping nude onto the beach together for the first time onscreen were interrupted by the quiet but firm sliding of the patio door.

Before your eyes had even finished flicking upwards, there was the flash of her hair colour to let you know it was her who was padding through and that you needn't be embarassed by her seeing you like this again. Your heart beat faster at being caught wanking in the living room by her to **** porn, and you thought about the different reactions she might have. As much as your fear rose, the new rules between you turned you on so deeply that you had to treat them at face value, you could never miss this opportunity, no matter what the risks of Charlie taking back her earlier words were.

Blowing all other thoughts out of your head, however, was the sight of her bare hips beyond the kitchen island. She was naked! She had been naked out there! Charlie had walked naked from her room to the outdoor shower and was planning on going back up nude as well, presumably. Had she been for a swim, too?

Lucy then appeared, and both of them seemed to be coming towards you. Your eyes try to drink them in as your hand pumps faster and your dick tries to harden to it's utmost.

Charlie whispered with a glance to the top of the stairs as she approached, "Mind if we sit down, too? We were watching you through the window." Her pussy was clearly visible, and Lucy's behind her. The shy look on her face was still eager as she had her tongue out between her teeth, unknown to you a sure sign she was horny.

"You're so naughty, letting your sisters see you wanking." Charlie gasped at you approvingly. Her and Lucy paraded in front of you before slumping into the other sofa to your side and pulling their knees up in similar fashions to each other.

You can't believe the look of arousal and excitement in Lucy's eyes as she stares between your face, Charlie's twat, the tip of your cock and her own fingers as she slid two of them rapidly into and out of her beautiful innie.

They must have already been masturbating to something like a comfortable rhythm at least while outside, because Charlie had also picked up a strong, lengthy stroke at a hard pace right off from pulling her feet up to her butt, which was pointing right out to you.

The view of these two amazing girls, exhibiting themselves like this kept you transfixed, while the video continued in the periphery of the room. You drag your gaze up to their faces, and the begninnings of an orgasm start to build as the reality of this level of momentary sexual freedom and lack of self consciousness from all three of you sink in. The girls aren't looking to the screen at all, but not really at you either, mostly their eyelids are fluttered shut, as the flustered, flushed expressions, tilted upwards and slightly slack, makes them look alluring in a way they hadn't before.

"I'm watching ****, by the way." You confess, dangerously and for no reason. With no plausible deniablility or way to climb down. "It really turns me on to think about flashing myself in front of sexy girls like this." And you feel your orgasm strengthening but for two more breaths no cum escapes you. Those breaths are long enough for Lucy to gasp and widen her eyes at Charlie saying;

"My big turn on right now is watching blowjobs. We can't do it, but can we watch Sara give you one tomorrow?"

You and Lucy both see white and hear ringing in your ears as vivid climaxes swallow you both.