Kristen quietly tiptoed up the steps, planning to surprise her brother. She had come home from school for winter break a few hours early due to lack of traffic, and figured she'd capitalize on the opportunity, if he was even home that is.
Up she went. One step at a time, careful to avoid that one spot that creaked really loudly. "All this better be worth it," she mumbled to herself, "I don't even know if he's home."
Throughout the years her and Mark and always gotten along quite well. When she went away to college last fall, they had kept in touch. They even told each other personal things. Mark knew about the boy she had been sortof dating sortof sleeping with, which her parents didn't. At nineteen, she had only slept with two men, but together her and her current on-again off-again boyfriend Billy had done massive amounts of experimenting, most of which she had told Mark.
Kristen began to think that maybe she told him too much, but it did go both ways, mostly. She hadn't told him everything, and presumably neither had he. She did know, however, that he had been dating some girl since last fall, right down to the night he lost his virginity. Although she had yet to meet the girl, Mark insisted that she was super cute and Kristen would love her.
Quietly, she passed the top step, and then planted her feet on the hallway floor. She continued down the hall, and noticed that the door to Mark's room was open. She was about to rush in, scream, and demand a hug, but instead stopped dead in her tracks, right in the middle of the doorway. Luckily, her surprised had kept her from audibly gasping.
What she saw she could not take her eyes off of.
Mark was sitting in his desk chair .... and some really hot naked girl was on her knees blowing him.
Kristen was unsure of what to do. She thought she should probably say something, or leave, but instead kept watching. Neither of them had seen her yet. To keep it that way, she stealthily backed up a few feet and peaked her head around the doorframe. The sight was turning her on, and she consciously moved her hand down her jeans and began fingering her slit.
"That has to be Katie," she thought, "Damn she's hot!" Then she heard something that surprised her even more.
"Oh, Kristy," came Mark's low guttural moan. Mark moaned, keeping his eyes on his girlfriend's head which was bobbing up and down on his cock. Katie really enjoyed sucking him off, and he never refused.
"Yea, you like that don't you?" the girl finally removed her mouth form his penis to speak. "Pretending I'm your sister. You wish this was your sister's mouth don't you? And your sister's tongue?" As she said this, she licked up his shaft and swirled the tip of her tongue around the head of his dick. "You wanna cum in your sister's mouth again?" Everything she said was so lustfully done. "Or maybe you want her panties?"
Kristen was furiously fingerfucking herself by now. Apparently her brother had been fantasizing about her ... with his girlfriend, and she was complacent with the whole thing. It was quite flattering. But confusing. She wondered how they had gotten to this point, and why it didn't bother Katie that Mark had been calling her a different name. No matter. She turned back to watch the action, while running a finger along her swollen clit.
Katie was now standing behind Mark, jacking him off with her hand, and Mark was holding a pair of pink panties that Kristen recognized as a spare pair she kept in her room at home. One of her favorites, actually.
Mark was getting close, and they all knew it. He let his head roll back and closed his eyes. Katie did her best to direct his dick so the semen shot into the panties.
"Kristy..." he whispered. "Yea, cum for your sister," was the response from his girlfriend.
Not wanting to get caught, Kristen quietly worked her way back downstairs, got back in her car, and drove around for a while. "Next time I think I'll ring the bell," she said to herself.
The next afternoon, Kristen was unpacking and cleaning up in her room. She was dressed casually, in a pair of sweats and a loose t-shirt, but still looked very sexy. A knock on her door. "C'mon in."
"Hey, Kris, just wanted to know what you wanted to do for dinner tonight -- Katie and I were thinking to get some pizza or something." They only lived with their dad, and he was out of town, wouldn't be back for a few days.
"Cool, pizza sounds great, count me in."
"Okay, I'll letcha know when its here." Before he left, Kristen spoke again to get his attention. "So I finally get to meet Katie tonight, eh?" She had not made any mention of the incident from yesterday.
"Oh, yea, you're gonna love her, she's so cute."
With that, he left, and Kristen continued unpacking, but not before looking him up and down as he walked away with a strange grin on her face. Sweaty, she decided to take a shower. When she came back, she need to find some clothes. For some reason, she looked into the dirty clothes hamper, and that's when she noticed the pink panties.
"He must've slipped it in with the rest of my dirty clothes hoping I wouldn't notice," she thought aloud. She picked them up and held them. It was obvious they still had her brother's dried cum in them from yesterday, and who knows how many other days maybe. Suddenly, an evil grin appeared on her face.
An hour later, her brother walked in the front door with his girlfriend. Kristen had spent the time alone laying on the couch. She was dressed in that infamous pair of pink panties, which felt so sexy to be in, and a black tank top, with no bra, and barefoot, without even socks
