The characters in this story are all over eighteen and the age of consent, sex if it happens is consensual. UK English is the rule: if the spellings Mum, arse or colour annoy you, don't go any further, for the rest of you enjoy.
*****
Chloe pulled Jack through the front door before flinging herself at him and kissing him hard. Her hands grabbed at his clothing pulling his shorts down and trying to wrestle his t shirt over his head.
"Chlo, Chlo," Jack said, pushing his sister away and removing his t shirt." What's going on, why the sudden rush, are you really sure about this?"
Chloe tore her sundress off and stood naked before him, moving forward she slipped her hand round his stiffening dick and began to walk backwards towards her bedroom.
"I don't know and I don't care, all I want is that lovely dick of yours in me, now", she fell on the bed dragging Jack with her and wriggled around until his dick was against her labia,
"Please Jack I'm begging you, fill me up, make me feel like a real woman." she slid forward until his dick was pushing into her opening, the juices evident on his cockhead dripping from her.
"Please, please make love to me," she urged, pulling him towards her and twisting herself to take him in. His dick slid in without obstruction and he found himself deep in his sisters vagina.
Chloe grunted with satisfaction as his dick filled her up. She moved gently feeling it moving inside her.
"Oh that's good, I love this, move more, please move it in and out." Her face was flushed and she began to roll her hips, and grip his dick with her muscles.
Jack felt as if a warm velvet hand was flowing up and down his dick. He began to move with Chloe and felt the pleasure rising inside him. Chloe was hanging on to his neck with her hands locked behind him. He move his mouth to hers and they kissed deeply. His little thrusts became longer, deeper. She gasped and yelped and grunted. Her breath became ragged and shallow, she twisted round and moved on top of him. Suddenly she began to yell and pumped up and down on him. She went rigid and he felt the pulses in her pussy ignite an explosion in his balls. Spurts of cum launched from his cockhead into her womb. She gasped and rotated and rolled her hips again using her muscles to milk his cock of every last drop of fluid.
Falling back she pulled him with her, they thrashed around until they lay on their sides, he inside her, their legs overlapping.
"Shit Jack, that was awesome, I love it, I want to do that all the time please. I love you so much." she kissed him hard and then softly. they lay there for a while, kissing, looking, feeling.