Too Intimate Sibs

Nathan and Lara aren't really siblings.at least that's what they tell themselves. Step-siblings can have sex, can't they? Even if they've been living in the same house for years? As much as they try they can't keep their hands off each other.so what happens when they try to invite their outside girlfriend and boyfriend into their too intimate relationship?This is a 10, 000 word novella intended for adult audiences.
Content warning: This story features graphic sex, group sex, sex of dubious consent, pseudo-incest, and other depictions of adult sexuality. Explicit language and adult only content. Contains content that some may find objectionable. Excerpt:"Yeah. You know what you're doing, " she complimented him. He was still on the floor kneeling between her spread legs. She wondered why he liked looking at her that way.
Then again, she wasn't a boy and the sight of a woman didn't especially turn her on."Can we have sex now?" he asked, standing up and lowering his pants. Her first instinct was to say no, and then she saw he was ready and realized something else was going on. "I'm guessing Lydia didn't give you a goodnight kiss, did she?""No, " he said, almost whining. She looked at the soft bed of blond curls around him and decided a quick bang wouldn't hurt anyone, as long as they were quiet."Fine, go ahead, " she said.
The words were barely out of her mouth and he was upon her. When he fell on her with his feet still on the floor she realized his shirt was still on. Lara didn't like that. She liked as much of his skin on hers as possible, but she was also still wearing her shirt and bra so it didn't really matter. What was most annoying was that he barely lasted a minute. She was about to order him back down between her legs, but then thought better of it."What was that all about?" she asked afterwards."Let's just say Lydia and leave it at that."