Unable to move her arms, but wishing to show her beloved brother the appreciation she felt he deserved for his new, tingling pleasure, Maryon thrust her hard body up at him, writhing a bit to rub her bare skin against his hairy thighs, unconsciously responding to the urge of sex, though she was as yet too young to understand or fulfill these instinctive movements. She only knew that his tongue in her mouth was sweeter than candy, more delightful than ice cream, more sensational than sparkling, prickling Coke… and nothing like any kiss she'd given or received before in her whole entire life! But intuition told her never to try this with Mom, or Dad, or anyone else she knew. Only with Mike! Daringly, gingerly, she closed her dainty little teeth on his tongue and, having trapped it, ran her own pointed prober around it as if it was a hot popsicle she'd gotten between her plump lips.
Mike was amazed and a little scared by his sister's enthusiastic response, and slowed down a bit. Already he was horny, though no more than piss-proud down there. With a last smacking suck, and a light peck on her blushing cheek, he concentrated on getting the nightgown clear of her. Devilishly she kept her arms stiff above her so that he was forced to extend himself up and over her, and he gasped as his swinging balls hit her chin, and he felt her lips pucker as they brushed against them. Struggling with her recalcitrant wrists, his eyes widened as his amazing little sister kissed his dangling flesh and let her impudent tongue lick along the cord that defined his two nuts.
Maryon was fascinated by the strange objects pressing against her face, and couldn't wait to have her hands free to explore there some more. Surely it'd been bigger than this earlier!? And harder!? Once he'd finally stripped the scrap of pink from her, she raised her head to shake out her mussed up curls, and so mashed her pretty flushed face against him. Again that odd flashing glow sparked through her, and she put her hand to it.
Not sure whether he altogether liked this sudden spurt of activity and inquisitiveness on her part, Mike sat back on one heel, then drew himself down against her, pulling the warm mass of bedclothes down over his chilling body. His sister, happy as a kitten, snuggled up against him and once more reached down for his cock. A sudden thought came to him. "Did you lock the door?" he urgently whispered in her ear. She shook her head. "Then you'd better hop out and do it, just in case," he said, pulling the sheet down from her to expose her once again. She shivered, made a mutinous moue then, sighing, slung her long slender legs over the side of the bed, and, on tiptoe still, made her way to the door and slowly, quietly as she could, thumbed down the lock.
Mike watched her as she went, sitting up in the bed with the clothes about his knees. As she turned toward him once more, smiling at him, with her body hunched and her hands on her opposite shoulders for warmth, he put his finger to his lips, then beckoned to her, then motioned with his finger until she was positioned, still hugging herself, in the center of the room, full in the bright rays of moonlight. Acting out for her with his own body what he wished her to do, he had her reluctantly move her hands until they were raised high above her golden head, high as she could thrust them, standing on tiptoe with her legs somewhat apart. Slowly she turned, with her gleaming hair falling down about her slim young shoulders, offering to his greedy eyes the whole, total view of her nude, slender, virginal body, with its flat breasts and hard cores of nipples which sent a pair of sharp black shadows down onto her silky skin, and the plump mound at the joint of her thighs, bare and brazen, and the firm creamy globes of her young girl's ass, with its black crevice between.
As she turned for the third time to face him, her eyes pleaded with him and, grinning, he nodded. What a slave she'd make – this eager, golden-haired sister of his, ten, tender and untouched.
She trotted rapidly to the bed and threw herself in with him with a slight protest of springs. "Careful, Sis!" he whispered in warning. He kissed her cool forehead, put his arms around her, and pulled up the bedclothes, holding her hard against him, silent, unmoving, until she was over her goose bumps and shivers and was warm again. Presently, she was content to let him do anything. He reached down and put his hardening cock between her thighs so that it stuck out behind them. At the feel of this hot bar of flesh between the satiny surface of her legs and up against her… Ass! Maryon let out a gasp and trembled with guilty pleasure, though why she felt shy and brave and ashamed and afraid and daring all at the same time, she couldn't have said. Placing warm, moist lips on his shoulder, she let her left hand run down her body, then behind it, until she could, by stretching a bit, just take his tip between three fingers and a thumb, squeezing and pressing, breathtakingly excited as she felt his thing growing larger beneath her cunt, and between her slim thighs. Using her thumb, she peeled his skin back ("What's that, Mike?" "Foreskin, Sis!" "Oh.") and since he was a bit longer there now, managed to get her tiny pinky to press its nail into the hole there. She could hear Mike breathing deeply, shakily, and could feel his heart pounding against her. It was getting stiffer, harder, longer… if only she could touch it freely.
Mike's own free hand was slowly smoothing the flesh of her side and back, a delicious feeling, so soothing… when suddenly he stopped.
"Wha…?"
"Ssshhh…!" he said. "Listen!"
There was a noise outside somewhere, in the house. Scared, all her 'grown-up'-aping confidence lost, Maryon made no resistance as, freeing himself from her, Mike roughly thrust her down along him and pulled the covers up to his chin.
"Don't move!" he ordered, sticking his head under the sheet.
She hugged herself against him, her head on his belly, her knees bent with one leg over his, arms clutched to her breast.
"It's Mom or Dad, going to the bathroom," he hissed again.
Suddenly afraid, knowing his manhood to be wilted, aware of the awful consequences, especially to him, if they should be discovered like this, Mike felt his heart hammering and his lips drying.
He listened keenly, straining to hear if footsteps would come down to this leg of the 'L', if the doorhandles of his and Maryon's rooms would be tried. Bet the little idiot didn't lock her own door!
Presently he heard the toilet flush again, doors open and close… then blessed silence. There was no movement in the bed with him. Goddamn! Has she gone to sleep, or what!? He put his hand down, under the covers, and ran his fingers into the silk curls of her hair. "Hey, it's okay now, you can come out," he said, tugging. But she hadn't been asleep at all, as he quickly discovered, just patiently and obediently waiting, for his signal was acknowledged by a juicy, full-lipped kiss about the hollow of his navel, and her sharp young tongue gouged into it to send shockwaves of pleasure through him. The cool mass of her soft hair slid along his belly as she moved down…
Trapped in the misty, musty warm darkness against the hot flesh of her brother, Maryon had felt against her thigh how Mike's cock had rapidly lost size and firmness, shrinking back and down softly against her. And wondered at it. How strange! What a funny thing to happen! The problem was… was his cock usually long and hard, and only getting smaller when he was frightened – for she'd worked that much out, that fear reduced it; or did it just come up big at special times… like when she played with it. But no, when she thought about it, she hadn't touched him the first time until he was already big and throbbing and hot.