18 year old Sarah had always been an adventurous girl. She loved exploring new places and trying new things. So when her older brother James suggested they go skinny dipping in a hidden lake near their house, she didn't hesitate to say yes.
As they stripped down to their bare skin and waded into the cool water, Sarah couldn't help but feel a sense of excitement coursing through her veins. The water was refreshing against her naked skin, and the thrill of being naked in the open air with her brother was intoxicating, she felt light arousal building in her pussy.
As they splashed around in the water, James suggested they play a game of truth or dare. Sarah eagerly agreed, feeling a rush of anticipation at what might be in store for her.
The first few dares were innocent enough - James dared her to swim to the other side of the lake and back, and Sarah dared him to do a handstand underwater and present his dick to the world. But as the game went on, the dares became more and more daring.
James dared Sarah to run around screaming "I am naked" and jump in the water afterwards. She did so, feeling the cool water splash against her skin, as she laughed and splashed around.
Next, Sarah dared James to lapdance her without touching their genitals. He obliged, grinding against her as she moaned softly. The sexual tension between them was palpable, and Sarah couldn't help but feel a growing desire for her brother.
As the game continued, they dared each other to swim between the other's legs without touching their genitals. They were not very successful and kept accidentally brushing against them every time. Sarah felt a jolt of pleasure every time James's cock brushed against her pussy, and she knew he was feeling the same.
Then, James dared Sarah to use her tits to splash water into his face. She complied, feeling her nipples harden as she squeezed her breasts together and watched the water splash against his face. They argued about what was more useful for splashing - her round, sexy butt or her tits - and eventually agreed to measure both by touching them.
James measured Sarah's tits and butt, evaluating which was better for splashing. Sarah felt herself getting aroused by his touch, and she playfully touched his balls in an ironic way to measure both for their splashing qualities.
Things escalated even further when James used his dick and balls to play propeller in the water, and Sarah couldn't resist touching his dick in a playful way that got his imagination going.
Finally, they started some sexy truths about their sexual desires. Both were already very aroused by what they were doing so Sarah tried to calm a little by picking truth. Little did she know what her brother wanted to know from her.
"Tell me, Sarah," James said, his voice low and husky. "Are you ovulating right now?"
Sarah felt a flush of embarrassment spread across her cheeks. She had always been open with her brother about her feelings, but she had never expected him to ask such a personal question.