All characters in sexual situations are 18 or older. Thanks for reading!
A pulsing glow cascaded out of the open puzzle. "What is that?" Nick stared at a black, faceted gem with red veins that was bracketed inside the cube. The veins were the source of the light.
"A weird crystal?" Alyson still held her brother's heavy dick in her hand. She squeezed it like she was holding his hand. "Do you think it's dangerous?"
"I don't know." Part of his brain urged caution. Maybe they should put the thing outside? But the rhythmic pulses of red light were mesmerizing. Nick continued to stare at it. It was fine, they had been around the puzzle for a while. "It's not dangerous."
"Yeah, probably not." Alyson leaned closer, her boobs hanging below her.
"It's pretty." Nick looked down at his dick. His sister's hand was now slowly pumping him. He could hear the wetness of their combined cum squelching in the quiet room. He hadn't lost his erection after sex, and there seemed little chance of his dick going soft anytime soon. "There's an inscription in Sumerian cuneiform." Nick pointed to a line of symbols engraved around the inside of the cube.
"The last riddle. We'll need Chris to translate." She had only planned on having sex with her brother the one time. The excuse had been to anoint the cube. But now, she needed him inside her again. She leaned forward and kissed his hard chest, her hand moving faster on his penis.
"We can't give the puzzle back to Chris." Nick let his sister push him onto his back. He could no longer see inside the puzzle, but he could see the red glow on the ceiling.
"We won't." Alyson put a finger from her free hand on his lips when she saw he was about to protest. "Shh. Don't worry so much. We'll find another way to translate it. You can help me. Sound good?" She straddled him.
Nick nodded up at her. Her hair draped over half her face. He pulled it behind her shoulder. "You're beautiful, Alyson." He read the room. She didn't have a kiss-me face. Her expression was less dreamy and wilder. Was this her fuck-me face?
"Since you already did it inside, there's no harm in doing it again." Alyson lifted her hips and placed him at her entrance. She was so sloppy that he slid right in. There was no pain at all.
"No harm? You said it was safe." He didn't want to get his sister pregnant. Worry creased his forehead.
"I said I was as safe as I get." Alyson laughed. She really should have been more concerned about... well... everything. But she felt too giddy to care. Amazing sex was a hell of a drug. "Don't fret, Nicky." She undulated on top of him, grinding their pelvises together. "'As safe as I get' is pretty safe. You know me. I wouldn't take any... uh... uh... stupid risks."
That was true. "Yeah... right..." Nick let the anxiety pass. They'd be fine. He leaned up and latched his mouth onto her nipple and drank.
"Ooohhhhhh... Nicky..." Alyson wrapped her arms around his shoulders and held him tightly to her breast. She wondered what would happen to them. She certainly couldn't go on humping her brother after she married Chris. She thought about all the time in the loops they had wasted not having sex. Why hadn't she seen what could be with her brother? She didn't understand her past, and she couldn't chart her future, but she could surrender to the moment. "Ohhhh... shit... Nicky... you're deep." And she chose to surrender completely.
They lost all track of time. Nick came inside Alyson and they barely paused. The light outside her window faded. Nick stood behind Alyson with his hands on her hips. "You're so... tight... Alyson."
"Not... ugh... anymore... I think." Alyson needed to teach him about holding her hair. That was the only thing between what he was doing and perfection. "Sometimes... Nicky... uh... uh... uh... a woman... wants you to... pull her hair."
"You want me to...?"
"Yes... yessss... please." Alyson's eyes rolled back when he bunched her hair in his hand and steadied her head. "Not... too rough... yesssss... like that... oooohhhhhhhhhhh." She slammed her ass back into him and came again.
When his sister stopped screaming, Nick thought he heard something troubling. He used all his willpower to stop his hips so their slapping skin and her squelching pussy wouldn't mask the sound. "Shit... the garage door. Mom and Dad are... home." He pulled out of her and his sister slumped to the floor.
"Oh... Nicky... I think... you've broken my... brain." She looked up at him and smiled.
"Mom and Dad... shit." Nick picked up his clothes, grabbed the puzzle, and turned to leave. He paused when his sister didn't get up. He couldn't leave her naked and leaking on the floor. He grabbed her blanket with one hand and threw it on her. "I gotta go."
"Okay." Alyson nodded but didn't move.
"Jesus." Nick wondered if he really had broken her brain. The threat of their father finding them should have been enough to light a fire under Alyson. "Put some clothes on... when you can." He left the room quickly. He could hear a door close downstairs. He darted into the bathroom and turned on the shower. He dropped his clothes and tried to close the puzzle. He found it closed, but wouldn't latch shut. A thin line of pulsing light shone through a seam in the metal. He put it on the sink and sighed. His cock was still hard and he wasn't going to put that third load in Alyson. Maybe next time. He stepped into the shower and got under the warm water. He was quickly fapping like crazy.
"You taking a shower, Nicky?" Kate's voice came through the door.
"Yes... I'll be out... in a minute." He stopped pumping.
"Okay, dinner will be ready soon. Come on down when you're finished doing... whatever you're doing in there," Kate said.
"Sure, Mom." Nick waited and listened. After a few seconds, he figured the coast was clear. He went back to fapping, imagining that his mom had joined him in the shower, and that she wanted him to pull her hair, too. He came while thinking about her round butt rippling with each impact from his hips.
~~
"What did you go shopping for?" Nick addressed the question to his mom, trying not to look at the smug smile on his father's face. He bit on a Brussels sprout and chewed. His sister, somewhat recovered from the afternoon, put her hand on his thigh under the table.
"Oh... um..." Kate's cheeks turned red. "We went clothes shopping."
"Cool, can you show me what you got after dinner?" Alyson's voice had a dreamy quality to it.
Fred laughed. "They're not the kind of clothes you can show to your kids. Right, Katie?" He raised his wineglass to his wife.
"Um... right." Kate tentatively clinked her glass against his and looked down at her food. "Sorry, Alyson."
"Oh, that's okay, Mom." Alyson looked at her brother and frowned. "I need to head back home after dinner anyway. Chris and I are going to the gym."
