Bobby and Hillary were the twin son and daughter of one of the wealthiest families in America. Being twins, they'd always had a close, albeit antagonistic relationship, which really hadn't changed as they'd gotten older; just eighteen now. But there was something weird about the way they felt about each other, ever since they hit puberty, which just felt stranger as they got older.
One day, Hillary took a bath. Mom and Dad were out of town, and Bobby was at DeMolay. One of her favorite things to do when she had the house to herself was to take a long, hot bath. She came out now, in her silk bathrobe, and nothing else, and laid down on her bed. A long soak always made her sleepy, and she dozed off right there on the bed, oblivious to the fact she'd left her bedroom door open.
Later that evening, Bobby came home. "Hill?" No answer. He went upstairs, to see if she was in her room. He found her door open, which she only did when she was in there, and not having her 'private time'. He went in. "Hey, Hill, you b-" He stopped dead when he saw his sister, lying on her back, asleep, and naked except for the robe, which was open. He knew he shouldn't stare, but couldn't help it. He started to feel funny, eying his sister's tits, then moving down her belly, and beholding her pussy. As he stared at it, he suddenly felt his cock swell up, till it was rock hard. He now felt compelled to do something he now realized must have been secretly on his mind all these years. He knelt on the bed, between his sister's legs. His heart pounding, he put one hand on her thigh, and caressed it, then pushed it aside, giving him a better look at his sister's cunt. He continued to run his hand over her thigh, a little rougher now. It was then that Hillary woke up.
Hillary just stared at her brother, who stared back at her. She could feel her heart pounding. Without a word, Bobby leaned down, and started eating his sister's pussy. It felt weird for Hillary, her brother's tongue gently tickling her down there. But she liked it. In fact, it was starting to feel really good. "Ouhm," she gasped. Her breath gradually sped up as her brother ate her out.
Bobby, meanwhile, liked the way his sister's pussy tasted; sweet, maybe a little salty. When she started to shift around, he held on to her leg. Hill's face started twitching as she felt it approaching. She bucked her hips, and moaned and squealed when she came.
Over the next few months, Bobby and Hillary acted like it never happened. They felt that, whatever it was, they'd gotten it out of their systems. That is, until that summer, when their parents went out of town again.
One warm, humid day, they started to feel it again, only stronger this time. At about mid-day, they were in their father's office, looking for something they'd stashed there. They were both looking in the credenza behind the couch, when their hearts started pounding. They stood up, and just stared at each other. Finally, Hillary looked down at the floor.
"Listen, Bobby, we need to talk about what happened."
"Yeah."
"I mean, we can't just deny it. That...was...incest."
"I know."
"I mean, it's like, I know it's completely wrong, but, I've been hot for you for so long. I mean, you're my fucking brother, but I can't stop thinking about you...in that way."
