Watch as Stephen fucks Katie

Marnie isn't going to lie to herself: getting eaten out by her sister had been as hot as hell. But that doesn't make her bi, at least not in her mind. She has zero desire to reciprocate.

It seems like Uhazral isn't going to let her off the hook. But letting—well, making, if she is being honest—Stephen have sex with her sister wasn't a bad thing, right? They were both adults. And Katie was arguably even hotter than Marnie, so if Stephen were a normal, red-blooded heterosexual American male, he would make only the tokenest of protests before giving into what was likely a fantasy of his.

Marnie doesn't plan on offering him any chance to make a protest, token or no. She takes a deep breath and closes her eyes, letting go of the will that she has unconsciously kept away from Uhazral's uncomfortable presence in her mind. Do it, she says to the demon. Make them … you know. So that they think it's business as usual. And aren't guilty.

Done.

Marnie opens her eyes.

Stephen has finished chopping and is drizzling balsamic vinegar into the salad. "Dinner's almost ready." So far he shows no signs of tearing off his clothing and ravaging Katie, who in the meantime has finished stripping down to her bra and panties and now looks at Marnie expectantly.

"Uhh …" Marnie frowns. How could she tell that anything has changed? "Um … Stephen, Katie's feeling the need for a little pre-dinner release."

"Is she now?"

"Come on, Stephen. Marnie's being a real bad sister and not helping me out after I just helped her." Katie puts on a pout to match the bratty inflection that has crept into her voice.

Stephen abandons the kitchenette, coming round the couch to face the two women. "I suppose there's time for me to help you with that."

Pointedly, Marnie moves off the couch, leaving an opening for Stephen. She hovers uncertainly next to the coffee table before shifting to the armchair. She has never watched before, and suddenly she flushes with unanticipated awkwardness. Of course, she hadn't told Uhazral to alter her in any way. Beyond her memories of frequent make-out sessions with her sister, Marnie still feels … well, like the old Marnie.

She could swear she feels amusement from the demon at her discomfort.

Stephen, meanwhile, wastes no time. He unzips his fly and produces his cock, already semi-erect from the sight of his girlfriend and her sister making out on his couch. Katie eagerly takes it in her hands. She cradles his balls and runs a finger along the hard shaft. It twitches and grows larger under all the attention. By every means average, Stephen's penis has nevertheless always managed to do the job for Marnie, and she sees no reason it should be different for her sister.

Still sitting on the couch, Katie wraps her thick lips around the cock. The purple head disappears into her mouth. Stephen lets out a small, contented sigh Katie takes him deeper. Her lips slide halfway, then three-quarters down the length of his shaft. One hand works his scrotum and testes. The other she slides down to her crotch and into her panties, rubbing herself in time to her mouth's pistoning up and down along the penis.

Marnie has to admit she's impressed. Katie clearly lacks anything resembling a gag reflex, and her sister is showing herself to be a proficient cocksucker. She is getting wet just watching … but dinner is almost ready, and so far they aren't showing much in the way of alacrity. So she interjects, "Guys, dinner's going to get cold."

"Then how about you grab me a condom, please?" Stephen asks.

"Oh! Right!" Marnie launches out of the chair and begins to head for their bedroom when Katie interrupts her cocksucking to say, "In my purse, sis."

Marnie shoots a glance in her sister's direction but otherwise refrains from any remark. Katie isn't in a committed relationship at the moment, so Marnie can only imagine what her sister is getting up to that encourages her to carry condoms in her purse. Still—better safe than sorry, she guesses. She easily locates the strip of condoms and tears one off, tossing it onto the couch.

Katie rips the wrapper open and quickly sheathes Stephen's cock. He is panting heavily now, clearly ready to fuck her senseless. But Katie has other ideas. She pats the couch next to her. "Sit."

Obligingly Stephen does so, pausing only to pull his pants and underwear down to make his cock a little more accessible. Katie too ditches her underwear. She gives him a few more pumps with her hand and then swings her leg over, mounting him like one would a horse … well, actually, not at all like anyone should mount a horse. She grips Stephen's shoulders and takes all of him inside her quickly and confidently. "Ohhh, yeah," she allows. "Mmm, Marnie. Your boyfriend's a nice fit." She smiles, looking Stephen directly in the eye. "You ready?"

"Fuck yeah," Stephen says. He works the clasp of Katie's bra, undoing it in seconds and sliding it off. Katie regains her grip on his shoulders and begins to ride him up and down. Her pink labia cling to his cock, slick from the lubrication provided both by the condom and her own, copious juices. Whatever she has been getting up to in her spare time with the boys, it clearly hasn't loosened up her tight 18-year-old pussy.

Marnie finds herself synchronizing her breathing with the two fucking bodies in front of her. Without realizing it, she has begun to touch herself as well. The fact that it's her sister recedes to the back of her mind; if anything, it makes it easier for her to imagine that she's the one being fucked. "Yeah, ride him. Fuck him hard," she mutters under her breath. "Make him come. Please him. Use him."

It's the hottest fucking thing she has ever witnessed. For the first time in her life, Marnie understands why people watch porn.

Katie is much more vocal than Marnie during sex. She whimpers and squeals happily as Stephen's cock fills her. For his part, Stephen has his hands around Katie's firm ass, pulling her close to him. He cranes his neck forward and manages to snag a nipple in his mouth. With an initial, shock, "Ow!" Katie quickly recovers and leans closer. Her bottle blonde hair falls around him, trapping him in a dark, sweet-smelling cave as he sucks happily on her bouncing tits.

It isn't long before Marnie brings herself to climax. Katie, however, takes a little longer. She increases her tempo, looking almost ****—or feral—as she thrashes about atop Stephen. He slides off the couch cushion a little, angling his hips so that his cock can hit Katie's G-spot more easily. This seems to work, and her moans soon become more intense and more pleading. The two of them seem to dissolve into a single, sweaty being of sex and passion. Stephen's hands roam along Katie's back and rear, squeezing and caressing and asserting unmistakable ownership over her. Katie's cries echo off the apartment walls. Her hair swings back and forth and her tits jiggle feverishly as her breath begins to catch. Her fingernails dig into Stephen's shoulder blades as she rides out her orgasm.

Stephen groans and comes as well. Katie reaches back and takes his balls in one hand, giving them several hard, mischievous squeezes. He reaches up and grabs her by the neck. The two of them, locked in this oppositional embrace, look at each other for a brief moment. Then Stephen pulls Katie's neck and head down towards him, his hand moving up to grab a handful of hair as he locks his lips with hers for a long, deep kiss.

They come up for air. "Wow," Katie says. "That was amazing."

"Yeah, you were."

"Careful! Marnie's going to get jealous if you keep talking like that."

Stephen looks over to where Marnie is sitting. "I think she's already jealous."

Katie wrinkles her nose. "Do you smell something burning?" The dull and insistent beeping of a timer is now far more evident than it was a minute ago.

"Shit—dinner!" Stephen extricates himself as quickly as he can without hurting Katie, setting her aside and standing. He just barely remembers to stop and pull up his pants before he sprints over to the oven. With all three of them lost in the moment, all had ignored to the timer's plaintive cries for attention.

Katie lies lengthwise on the couch, absently touching her nipples and clit, a goofy smile on her face. "You all right over there, Marn?"

"Mmm, fine," Marnie says. "Just … wow. You certainly were something there."

Stephen announces, "It's not too badly burned. I think we can salvage it. Can one of you set the table?"

"Me, something?" Katie says. "Nah, I'm still just learning. I've never actually tried that before—but I always wanted to. It was nice to have a guy who actually listened to me for once."

"Well, you could have fooled me." Marnie gets up and complies with Stephen's request.

"Actually, I was kind of hoping I'd have the opportunity to get some more tips from you and Stephen in that department."

"Oh?"

"You guys have an extra room in this place, right?"

A fork hovers just above its setting on the table. "Yes…."

"I need a place to live in town now that I’m starting college. I was thinking I could move in." Katie grins. "Maybe … join in."