I slammed the front door shut and heard the wet sounds coming from the living room. My cock twitched instantly.

There was Mom on her knees, her big tits hanging out of her open robe, slurping on my brother's dick like she was starving. He had his hand fisted in her hair, pumping his hips, fucking her mouth raw.
"Fuck yes, Mom, take it all," he growled. She moaned around his thick shaft, spit dripping down her chin onto her heavy breasts.
I didn't even knock. I just walked over, unzipped, and shoved my own hard cock into the scene. Mom's eyes flicked up to me and she grinned around the dick already stretching her lips. She pulled off with a pop and turned, grabbing my cock and swallowing it down in one sloppy motion.
"Both my boys," she mumbled, voice thick with spit. "Give Mommy what she needs."
My brother stripped the rest of her robe off and spread her ass, driving into her pussy from behind while she sucked me. The wet slap of skin filled the room. Mom's tits swung as he pounded her, and she kept moaning on my cock, the vibrations making my balls tighten.
We didn't stop there. Later that night my sister walked in on us. She was eighteen, just like me, and she stood in the doorway watching Mom ride my brother's cock while I fucked Mom's mouth again. Instead of leaving, my sister peeled off her clothes and crawled onto the couch.
"Room for one more?" she asked, spreading her legs and rubbing her shaved pussy.
I pulled out of Mom's mouth and shoved my cock straight into my sister's tight cunt. She was soaked already. "Fuck, brother, your dick feels so good," she hissed, locking her legs around me. I hammered into her while Mom climbed off my brother and sat on his face, grinding her dripping pussy on his tongue.
We switched around all night. Mom rode my sister's face while my brother and I took turns fucking them both. My sister came first, screaming into Mom's cunt as I flooded her pussy with cum. Then Mom bent over and took both of us at once, one cock in her ass, one in her pussy, while my sister licked wherever she could reach.
By morning we were all sticky and sore, but nobody wanted to stop. Mom looked at the three of us with a filthy smile and said, "Same time tomorrow?"
We all nodded. This was our family now.