He hated it when his parents made him babysit his sister, after all he was sixteen and would much rather hang around with his buddies ogling girls his own age at the mall. His sister was just a few weeks shy of her thirteenth birthday, and in his opinion, still a silly little girl.
As soon as their parents left, he told her to find something to do and leave him alone, as he wanted to give his best friend a call and tell him about the new girl he'd spotted that afternoon. He heard her stomp up the stairs as he dialed the number, but then the two boys became so engrossed in their conversation that he never heard her come back downstairs and slip out the sliding doors to the pool area.
The boys talked for a few more minutes and then hung up, and he realized that he needed to get something for his sister and himself to eat. He went into the kitchen and made a couple of sandwiches, grabbed some chips from the bag for each plate, and yelled for his sister to come and eat.
There was no response. He went looking through the house, checking her room and the bathrooms, the den and family rooms only to find them all empty. As he was approaching the sliding doors he heard a splash and realized that she was in the pool.
He opened the door and yelled again for her to come eat, turning away as he did to head back to the kitchen. She followed him in a minute later, clad in a bikini that left little of her young body concealed.
The pale blue cloth stretched over her already somewhat developed breasts and ass, but failed to hide the erect nipples and alluring outline of her sweet virgin pussy.
Suddenly he realized that his sister was becoming quite a charming and sexy young lady, and he turned away from her quickly, going to the fridge to get them sodas to hide the fast growing bulge in his shorts. He knew he shouldn't be aroused by his own sister, especially as young as she still was, but he just couldn't help himself.
Usually when their parents were home, she wore a one piece suit that covered more of her and made her look even younger than her almost thirteen years. When he turned back to the table, she was already wolfing down the sandwich and chips and appeared to be unaware of the reaction she'd caused. He sat opposite her and began to eat, the two of them not speaking as the food disappeared.
When she was done, his sister took her plate to the sink and his teenaged cock again roared to life as he watched her buttocks sway as she moved. She told him she was going back out to catch the late sun, and he decided at that moment to join her by the pool as soon as he could get his swim trunks on. He knew that their parents would be gone at least another four or five hours, and he wanted to watch his sister some more as vague thoughts of what it would be like to fuck her tight little cunt started rolling through his mind.
He had played around with his girlfriend as often as she would allow, but was still very much a virgin himself when it came to actually fucking a girl. He raced up the stairs to his own room and pulled off his shorts, reaching for his swim trunks as his cock waved in front of him as if seeking the warmth and wetness of his sisters' pussy already. Back down the stairs and to the glass doors he ran, only slowing as he got to where he could see his sister lying on her stomach on a lounge chair, her top undone so she wouldn't have a tan line.
From where he stood he could see the length of her body, the side of one breast seeming to beckon and call for his touch. Her face was turned away from him and he could almost imagine that it was an unknown girl laying there waiting for him to come out. He took advantage of her not looking to step quickly outside and run to the pool, diving in to hide the raging hard on he had. At the sound of the splash, she jumped and for a few seconds her whole upper body was completely exposed, though her brother didn't see as he was swimming the length of the pool.
By the time he reached the other end of the pool, she had her top back in place and was preparing to dive into the water herself. As her body arched into the water, her brother pushed away from the side of the pool where he'd been hanging afloat as he watched.
They met in almost the exact center of the pool, their bodies colliding in the cool water. Both of them submerged from the collision and flailed to resurface to the air. His hand rubbed one of her breasts as they rose back to the surface, and he felt her fingers brush against his hard cock. They broke the surface and he found himself so close he was almost touching her.
Without thinking he reached out, pulled her to his chest, and kissed her; one of his hands finding a breast and nipple.
She struggled for a moment but was very quickly overwhelmed with a series of new sensations that made her want her brother to continue kissing her and feeling her up as he was doing. Her hands began to explore his body as well, and she gasped as she found his cock straining against his trunks. He was drifting them closer to the side of the pool as they explored each others bodies, and she suddenly found herself pinned between the side of the pool and her brothers' body.
he was stripping her suit from her, the top already gone and floating to the other side of the pool, his hands now sliding her bottoms down over her hips.
She kicked them off and spread her legs as his fingers slid between them to find her pussy lips, accidentally scraping across her clit and sending a shudder through her.
He was rock hard and aching, his teenaged cock more than ready for the feel of a tight pussy wrapped around it, his excitement beyond his control. He lifted his lifted his sisters legs, and moved forward the few inches that separated him from his goal, his cock seeming to aim itself at the virgin pussy now fully exposed before it.
He settled against her and began to work himself into her slowly, her tight hole feeling so good to him until he found the barrier of her hymen. Looking in her eyes, he gave one solid shove and broke through it, her scream of pain fading quickly as she felt him sinking into her, filling her up and sending still more new sensations roaring through her body. They moved together briefly, his control, such as it was, disappearing fast as his cock felt her smooth tight pussy instinctively contract on his length.
She was shuddering against him and he felt his balls tighten up as he prepared to explode inside her. A couple more strokes took him over the edge and sent him to a world of ecstasy; he lost himself in the feel of his own orgasm and his sisters' tight and incredibly hot pussy milking him dry. Brother and sister floated in the water, catching their breath as he slowly shrank and slipped from her still clutching pussy.
He knew what they'd done was considered wrong, but he also knew that they would do it again.