Crossing Lines

"I'll be quiet. I promise. Just don't stop." She begged. With that he shoved his face back between her legs and his tongue went back to work.Shelly sucked on her lower lip, fighting the urge to moan as his soft, hot tongue circled her aching hole then lapped up her dripping lubrication. He traced his way up to her clit, making her bite down on her lip when he pressed his tongue down firmly over her clit and shook his head gently back and forth.

He worked his tongue around her pussy until she was soaked and shaking then sat up high on his knees and pulled his dick from his pants. He entered her smoothly and easily. He thrust into her as he lifted her shirt and buried his face in her bare breasts. He sucked her left nipple into his mouth, getting it hard then teasing it the same way he had with her clit. She quietly panted, her whole body shook as orgasm ravaged through her, tightening her muscles around his thick shaft and making him push harder inward as her muscles pushed him out. She felt his cock expanding inside her, letting her know he was about to cum too. She pumped her hips into his, trying to help get him there.

"What the fuck is going on here?" Their Dad's voice boomed from the bottom of the stairway.

Shelly froze instantly, terrified. Her heart pounded in her chest. Her brother's cock throbbed in that moment just before Dad started talking, she'd felt it happen, she'd felt it begin to spit inside her. It was too late, nothing would stop it now but Steve stopped moving, his face instantly draining all color. He pushed away from his little sister but being mid-orgasm his body didn't respond to his mind. He fell backward, landing on his butt. His cum still shooting out of his hard cock. Shelly watched in horror as he finished cumming, shooting thick, stringy globs onto the living room carpet and his pants. His dick gave one final throb, pushing out the last, sad blob of cum that dribbled down his length. As soon as it was out of him, he went limp and his face burned red.

"What the fuck did I just see?" Dad looked down at Steve then over to Shelly. "Cover yourselfs up." His voice was more hushed this time. Anger and disappointment dripped from his words.

Snapping back to life, Shelly tugged her shirt down and fixed her shorts as she sat herself up. Steve pulled his wet pants over his limp prick and sat himself up also. "Daddy I'm sorry. I'm sorry it was my fault." Shelly cried. Tears instantly streaked down her cheeks.

"Shut up." He growled. "Shut up."

"Okay, Daddy. Okay I'm sorry Daddy." She blubbered.

"She's your sister! Your LITTLE sister!" Dad's voice growled again, this time directed at Steve. "What are you fucking doing to her?"

"I... I don't... I... didn't" Steve failed to find any words that would explain what he was doing.

"How many times?" His eyes glowed with fury as he looked between the two of them. "How many?" He repeated.

"I.. I... I don't know." Steve managed.

"It's my fault Daddy, I made him." Shelly said softly.

"Go to your fucking rooms. I don't want to hear any more. This never happened and your Mother is Never to find out about this. Never! Do you understand me?" He waited a moment. "I said, Do you fucking understand me?" Shelly and Steve nodded in unison. "If this ever happens again I'll make you both regret it. Now GO!" His final words were growled so low the two could barely understand him but they knew what he meant. Shelly was on her feet before Steve but they made it to the hallway at nearly the same time. They scurried into their rooms, shutting their doors at the same time.