[Sorry this took so long. It's a sequel to "Drunk Sister," obviously, but no need to read that first unless you want to.]
[Oh yeah, everyone's over 18. And there's some lesbian sister sex, in case that bothers anyone.]
"What the fuck are you freaks doing?" Madison yelled.
Danica and I were sitting on the bed. Naked. My cock was still dripping.
My sister Danica came home last night drunk. She flirted with me. I tried to ignore it, and I helped her up to her bedroom where she finally passed out on her bed. Naked. I didn't do anything then--okay, I jerked off looking at her, but she was asleep and I wasn't going to do anything more than that while she was drunk.
Then this morning she seduced me. This time I didn't resist. She sucked my cock down in the living room, and then we came upstairs to her bedroom where we fucked and sucked each other until we had to take a break. That's when Madison came home. Our older sister. And walked in on us, naked and sweaty and ready for more.
Danica laughed. "What does it look like, Maddie? We fucked." She patted my leg, teasing my dick with her fingers. "It was good, too."
I smiled. My cock twitched.
Madison's face turned red. "You fucked Trent? Your brother? Our brother? My brother? What is wrong with you?" She turned to me, then looked away so she wouldn't see my cock. "Trent? How could you and her--" She stopped, out of breath.
"Relax, Maddie. Here, have a drink." She held up the half-empty bottle of whiskey we'd been drinking.
Madison shook her head. "You can't do this."
"It's just sex." She took a swallow of booze. "Come on, you never thought about it? I know you did."
Madison's eyes jerked toward me involuntarily. For a moment she tried to look away, but after a moment she stared at my naked body, looking me up and down. My chest, my shoulders, my legs--and finally my cock. She bit her lip and shook her head, staring at my hardening dick.
"I can't believe you did that," she said. "You bitch. Do whatever you want to do. I won't bother you." She reached for the door.
"Maddie, wait." Danica jumped up and grabbed Madison's elbow. "You had plenty of chances. It's not my fault."
Madison glared at Danica. "Bitch. I can't even--" She looked me over again and sighed.
"What's going on?" I asked.
"Okay, here's the story." Danica plopped down on the bed. "Once upon a time..."
___
It was the summer I had graduated from high school at 19. Madison was still living at home. I was out with friends one Saturday night, and Danica came home late from a party.
Our parents were asleep. Danica stumbled upstairs, trying to be quiet and not wake anybody. She passed Madison's bedroom, and saw the door wasn't closed all the way. And she heard sounds inside.
"Umm... uhh... ahh... ohh..."
Danica grinned. She knew those noises. She made them herself when she was alone.
Giggling, she crept to Madison's door and peeked in.
Her older sister sat on her bed, legs crossed, in a T-shirt pulled up over her shoulders. Danica could see Madison's boobs bouncing gently, and saw one arm moving back and forth, her fingers between her legs.
"Oh... oh... oh..." Madison moaned, her eyes closed.
As Danica watched, Madison's fingers moved faster, and her breathing got louder. With her free hand Madison started stroking her nipples, rubbing her tongue over her lips. "Oh... ah... yeah..."
Danica could see Madison's laptop perched on the edge of her bed. Was she watching porn? She didn't think her sister was the type. She knew Madison had broken up with her boyfriend a few weeks ago, and she hadn't been on a date since. But she was human, right? She got horny like everyone else. Danica grinned, seeing a side of her sister that she never would have guessed at.
She leaned in a little further. Madison was so lost in her stroking and sighing she didn't notice. Danica peered at the computer screen, wondering what she was masturbating to--
And saw a picture of Trent. Me. Her brother.
It was a picture of me in a pair of Speedos. Probably from one of our vacations to the beach. The Speedo didn't hide much, and I guess my body looked all right.
"Ohh!" Madison moaned, leaning forward, gazing at the screen. Her body twitched on the sheets. Danica watched and slowly started rubbing herself under her panties, trying not to breathe too loudly.