So, I’m sitting at the kitchen table, scrolling through my socials, when I find something interesting. “Hey, Zoe, look at this,” I say, and then realize that she’s not sitting at the table with me anymore. I turn around and see her standing at the window gazing out into the backyard. “What’re you looking at?” I ask, standing up.

“Oh, nothing,” she replies dreamily.

I go over, stand behind her, and look over her shoulder. “You’re looking at my little brother,” I accuse.

“Hmmm,” she agrees, still clearly zoned out. “Not so little now, though.”

I reach around her and slip my hand down the front of her shorts and into her panties, resting my middle finger along her slit. “Feeling a little moist here, babes,” I whisper into her ear. “Are you fantasizing about fucking Ryan?”

Zoe and I have been having sexy fun and games since we were ... about fourteen, I guess. For sleepovers, we always dutifully carried a sleeping bag to the other’s house, and then left it studiously alone as we slept together in the one bed. But that’s another story. Let’s just say that she isn’t surprised at the liberties I’m taking with her body. Or, indeed, unhappy; leaning back against me and grinding her fine ass on my crotch.

Another hand on her boobs confirms that her nipples are as hard as bullets. God, she’s horny as fuck! The tip of my finger dips into her now slick opening, and transfers some of her wetness onto her clit hood.

“So cute,” she moans. “And so young!”

I love my baby brother to bits, but I hadn’t really looked at him for a while, and I have to admit he does look pretty good: stripped down to just a pair of shorts, his skin glistening with sweat as he does the first mow of the year; one of the many jobs our folks left us to do while they’re away. Zoe is moaning softly, pumping her groin into my hand and getting wetter by the moment. I realize that Ryan’s bulked up a fair bit since I last looked at him properly, and now has a nice shape to his chest, and even a little six pack going on; not bad at all for a sixteen-year-old.

I’m not entirely sure if it’s what I’m doing to Zoe, or the way that her butt is rubbing on my clit, or the sight of my little brother that’s turning me on, but something certainly is!

We stand there, both watching Ryan working hard, bending down every now and again to empty the cuttings, making his shorts stretch over a very firm-looking little ass, while my finger traces a path between her now very wet vagina and her clit. After a while, I feel by the way her pussy is rhythmically gripping my finger that she’s getting close. And then Ryan wipes the sweat from his forehead, and dries his hand on the back of his shorts.

“Oh, God,” Zoe hisses, because it looks for all the world as if he’s fondling his own tight ass for our delight. Her vagina clenches hard around my finger, and her back arches. “No!” she cries softly and mournfully. “Please, no!” Ryan is walking back toward the house!

“I’ve had enough for today!” he shouts as he mounts the stairs. “I’m going for a shower.”

I keep gently stroking and fingering her, but I can feel that the moment is passing. Then I have a brainwave: “He never locks the bathroom door,” I whisper into her ear. “Mom’s always chewing him out about it.” She turns her head to look at me, a desperately hopeful look on her face, while my finger is nearly crushed. “We could just peek around the door...?”

Her eyes go wide with excitement, and then she pulls my hand out and sucks on my fingers - she really does love her own taste - and I can testify that it’s with good reason. Having her suck on my fingers adds to the tingling in my own clit, and I think I may be almost as desperate as she is to see what my little brother was hiding in those shorts.

She takes my hand and leads me upstairs. The door to his room is open, and we continue along to the bathroom. Zoe starts to reach out to open the door, but I grab her hand, shaking my head, mouthing ‘no water’ to her.

She pouts, and then grins as I resume where I left off downstairs. She gives me a little kiss as I slip two fingers into her hot little puss, and pull her ass hard against my body. Only a few minutes later, we hear the shower start running.

My heart is beating fit to burst as Zoe reaches out and turns the knob, and the door starts to open. I pinch her arm as she lets out a low moan as we both see his gorgeous, dimpled ass cheeks through the crack in the door. “Shush!” I hiss into her ear.

He really is quite beautiful, and I can’t resist pushing Zoe’s T-shirt up over her boobs so I can play with them properly. She wriggles in my arms, clearly enjoying that, so I start trying to push her shorts and panties down with the other hand. She freezes momentarily, and then helps, pushing them down to her knees. Zoe is a bit of an exhibitionist on the quiet, and I can tell that being almost naked is turning her on like crazy; she can’t keep still, and her pussy is almost gushing. I continue to frig her and squeeze her pert tits while Ryan washes his back with the loofah and then soaps up his ass with his hands.

Then he turns round, and we both see his cock for the first time. The view isn’t perfect, because of the wet glass, but it’s semi-erect, and a remarkably nice size for his age. I see him peering at the gap in the door and frowning, as if not quite sure what he’s seeing, and then he opens the shower door, and we can see him perfectly in all his young glory. In a moment of utter, lust-crazed madness, I push the bathroom door open further, and his cock rises rapidly as he sees his sister with her fingers in her best friend’s pussy, while she plays with her boobs.

“Oh, God!” Zoe cries as she feels his eyes all over her mostly naked body, and sees his cock, now fully erect and beautiful. She starts to tremble in my arms, and I know from experience what that means. Then Ryan wraps his fingers around his erection, and he starts to jerk himself off.

The sight of my little brother masturbating has Zoe panting for breath, and her hips jerk spasmodically as she loses control of her legs. “Faster,” she gasps, “Please ... harder.” I’m not sure who she’s talking to, but my fingers flash in and out of her as I try to help her out. Ryan’s hand moves faster as well, rubbing his palm over his shiny knob. “Yes,” she whimpers, and I can tell she’s agonizingly close.

“Oh, God!” Ryan groans, and his hips give an almighty jerk, and he blasts a jet of cum that lands at Zoe’s feet.

“Yes! Oh fuck, yes!” she cries, her claw-like hands clutching painfully at my thighs and her legs cross, trapping my hand in her wildly spasming pussy.

My best friend cumming in my arms, and my naked little brother continuing to spurt arc after arc of sperm onto the floor from his lovely cock, are too much for me too. I pull Zoe hard against me, in the process ramming my fingers even deeper into her vagina, and grind my swollen and erect clit on her bare ass until I’m cumming too!

It is a truly special moment: having an orgasm at the same time as two of the people I love most in the world, and it feels utterly magical. Then the high begins to wear off, and suddenly it becomes very, very awkward. “Um...” I say uncertainly. “Erm ... run? Yes, run!” I turn and flee down the corridor until I hear a plaintive cry of “Help.” from behind me. I turn and see Zoe, hobbling along with her clothes still around her knees, her boobs jiggling away madly, and I can’t help it: I double up, laughing uncontrollably.

Somehow we help each other to my room and then collapse on the bed in fits of giggles. “What did you do?!” she demands to know when we can speak.