Don't be too hasty.

Gary did what he thought he was meant to do and started to lift up so that he could pull free of his sister. He’d only gone inside by accident because of how wet and slippery his cock had become from Lil’s bubbling pussy. As he started to pull out, Lil reacted.

“No, please! Don’t stop,” Lilian begged as she grabbed Gary’s arse with her hands, driving her nails into him and then locking her legs tight high on his back.

“That’s it! She loves it,” Bernice encouraged, not knowing that Lil’s reaction was from having Gary’s cock inside her for the first time ever.

Gary was in astonishment as he relented and reversed his momentum and drove his shaft back inside his sister. He was really doing it! He was fucking Lil. Damn, she had the tightest little pussy on her, he thought. The way it gripped his cock and latched on had Gary seeing stars. Steve had been able to get this on the regular, and he still cheated on Lil was incomprehensible.

With the change from pretend to real, loud, wet slapping noises started to come from between the two siblings as Gary beat his meat into Lil’s dripping box. She was a squirmer beneath him, never still for a second as she writhed and responded to every hard stroke of his dick. Gary was glad Lil was attached to him so tightly, or he may have been thrown off.

In the position they’d been in before, Gary’s veiny cock had been grinding up against Lil’s clit nearly the entire time, so that she was already primed for fireworks by the time Gary had accidentally gone inside. As he pressed on and fucked her thoroughly, Lil felt her body start to tense and then snap like a spring wound too tight.

“Gary, I’m cumming!” Lilian screamed as she erupted in the most unexpected of orgasms.

Gary gasped as Lilian’s pussy contracted, and his cock was given barely enough room to survive. Bernie always tightened up when she came, but this was on a whole other level.

“Woooo!” Bernie whooped to the sound of Lilian straining and thrashing on her boyfriend’s cock.

Gary maintained a rhythmic flexing of his hips that rocked his cock inside Lilian’s cunny all through her climax. It was only when she had slowed down and was panting in recovery that he finally pulled his cock free, feeling suddenly self-conscious as he loomed over his little sister's **** body.

If Bernice had been able to see in the dark, she would have seen Gary’s hard cock glistening, polished, wet with Lilian’s heavy steam.

“Did you want him back?” Lilian asked, her voice coming through all crackly in her lightheadedness.

“Only if you're done with him,” said Bernie, which got the girls giggling manically.

“Just for now,” Lil tittered.

Gary lay in the dark waiting for his girlfriend to take over with him as Lilian made a suggestion to the group. “Show me the Bouncing Spoons.”

Lil couldn’t see what was happening, but would soon be able to feel as Bernice helped her boyfriend to sit up at the head of the bed. Gary then held Bernice’s hips as he guided her down on his cock as she faced towards Lil.

With her shins tucked back under herself, Bernice started to ride Gary in full hops of her body that drove his cock nearly in and out of her each time. Gary assisted to make sure she always travelled the required distance and stayed on the true path along his hardness each time. Lil crawled over towards the pair and kneeled in between the lovers’ legs as she caught one of Bernice’s breasts and started to suck on her erect nipples. With her free hand, Lil reached down and massaged Gary’s full balls as they became ever more sodden by the passing second.

Where Lilian had been constrictor tight, Bernice was much looser and flowed freer and faster along Gary’s manhood. His girlfriend seemed to have the wetter pussy of the two as Bernice dribbled much of her pussy juices onto Gary’s lap as she mounted his flesh tube. When Bernice started to cum, her pussy shrank down in size so that Gary was once again held so snuggly, but not to the degree that Lil was. Gary was convinced that Lilian had helped to bring his girlfriend to climax by rubbing her sensitive bean during the final straight. While she moaned continuously, Gary kept a good hold on Bernice’s hips as she rocked her hips in place in languid rolling motions. The bouncing forgotten as Bernice pulsed upon him at full depth.

Some 90 seconds later, Bernice slid her way down Gary’s thighs, causing his cock to be pushed down flat until it came free of her pussy with a splotch and sprang back into place tall and proud.

“Did you want to try that?” Bernice asked Lil, offering to trade places once again.

Lilian paused for a moment to think about what exactly that would mean. Before it had been an accident and she hadn’t meant for Gary’s cock to skate inside her fanny. She hadn’t intended to cum all over it with frightening intensity either; it had just happened as an unexpected consequence. If she said yes to Bernice now and allowed Gary to enter her again, it would be by conscious decision. Lil would have to want to fuck Gary. On the one hand, that was wrong; they were brother and sister. On the other hand, she was really fucking horny right now, and she could put it down to a one-time thing, and accidents happen. She’d never do it again after this. Fuck! She realised too late she sounded just like Gary had this afternoon when he’d admitted to cheating on Bernice with Laura. Bugger it, Lil decided. A girl really needed to get laid and it was a once in a life time experience.

“Ok,” Lil voiced. “Gary let me go again.”

Both of the girls had orgasmed by then, and Gary was eager to even the score. As Lilian’s cock-hugging pussy was lowered back in place, Gary couldn’t help but drive up and fucking her aggressively from below. With each purposeful thrust, Gary slammed Lilian’s pussy down against him as he manhandled her selfishly. He wasn’t truly thinking that this was his sister he was fucking anymore, but that it was a moist and willing pussy that wanted him just as badly as he wanted it.

Lilian’s perky tits felt like they were ready to scorch someone as Gary groped and pawed at her slender frame in the moments before he called out, “I’m going to cum any second.”

“Do you want to take this?” Lil asked Bernice as she hopped quickly off Gary’s primed and ready to explode dick.

Gary didn’t wait for Bernice to be ready as he rose up and pushed her head first down into the mattress and then snatched her hips and brought them around to face him. He plugged himself into Bernice’s socket and, in just five hard stabs, started to flood her with his hot white cum.

“Fucking take it!” Gary cried as he plunged his rod deep within Bernice’s guts, trying to rearrange her insides. She could feel every hard little jet of sprog as it crashed against the walls of her cervix and stayed there, building up a thicker coating with every successive stream. Gary almost toppled over onto Bernice’s back in his ****, unending need to skewer his cock inside someone.

Lil could hear Bernice’s bubbling and venting gas when Gary finally pulled out of her and left her pussy a sticky mess of his male excitement. She had to resist the urge to reach out a finger and taste it, only stopping because it was her own brother’s jizz she’d be eating.

It was a struggle for each of them to get themselves back into a proper position so they could sleep afterwards. Lilian and Gary ended up on either side of the bed with Bernice in the middle of them. Lilian liked that as it gave her Bernice’s large and pillowy breasts to rest her cheek against as she drifted off into unconsciousness. The post-nut exhaustion that settled fast onto Gary didn’t give him a chance to even think about things other than ‘that was freaking awesome’ as he dropped quickly into sleep. Bernice was the last one to fall asleep. Glad that she’d introduced the siblings to each other, as it allowed her conscience to get a little sliver of peace over what she herself had been doing.