18-year-old Susan got out of the pool and checked her phone. “Shit!” she said, “Mom needs me to drop something off at her work. I’ll be back in a bit, nerd.”

The target of that label, her 15-year-old brother Chris, nodded as he sunbathed. Behind his sunglasses, his eyes followed her sexy teenaged body in her one-piece swimsuit as she headed back inside the house.

Susan took off her swimsuit, hung it to dry in the shower, and changed into her street clothes. Then she grabbed the papers her mom needed and raced out of the house. The hot summer had just started and she wanted to get back to their pool to cool down!

When she got back she immediately removed her clothes and grabbed her swimsuit. It was still damp -- she hated that! -- but she stepped into it anyway and pulled the straps up over her shoulders. Brr!

She quickly left the bathroom and strode back out to the pool. It looked as if her dweeb brother hadn’t even moved in those 20 minutes! She didn’t see his eyes upon her, widening in surprise and delight as she jumped back into the water.

Twenty minutes ago...

Once Susan was out of sight, Chris took out his own phone and crept over to the slightly open window of the bathroom. He turned on the video app and poked the camera lens over the lip of the window. He was taking a terrible chance that she would see it, but on the screen he could see she was facing away from him as she changed.

He held his breath in order to keep the phone steady. He could see sideboob as she pulled her swimsuit off her shoulders, and then her perfectly formed ass as she pulled it all the way down and off.

She was in a hurry, so as she turned to grab her street clothes she didn’t notice the phone. Her brother got a full frontal shot, and he just about choked at seeing that!

Then she pulled on her cut-offs and half-top and was out the door with flip-flops in hand.

When Chris heard her car roar off, he headed into the bathroom. He had been sniffing his sister’s used panties for a few months now while whacking off. Now, not only did he have a fresh target, he also had a video he was going to watch every time he pleasured himself from now on!

He pulled his sister’s bathing suit down from its hanger and brought the inside of the crotch to his face. Sniiiifff! Heavenly! Kind of a salty smell, almost fishy, with a bit of chlorine.

His cock was already hard from taking the video, and he pulled his swim trunks down to free it. He sat on the toilet seat and called up his video app.

As he wanked his teenaged cock with one hand he watched the video of his sister undressing. He paused it when she turned toward the camera, and...

... he couldn’t believe it. He stopped masturbating so he could pinch and zoom.

His sister’s crotch was completely shaved! He hadn’t caught that at first because he had been focusing on her fantastic boobs.

That was it ... he was going to cum just at the sight of his older sister’s shaved pussy. He grabbed her swimsuit and covered the head of his cock with the inside of its crotch just as he unloaded. “Unh! UNHH! Oh shit!”

As his breathing slowed, he couldn’t believe how hard he had just cum! It had never felt that intense before.

He looked down at the mess he had just made of his sister’s swimsuit’s crotch. He was going to wash it, but then he realized that it would take too long, and anyway the inside of the crotch was made of a white material, so unless you really looked you couldn’t tell that anything had happened.

Just then he heard a car coming up the driveway. Chris rushed to get his sister’s swimsuit back onto its hanger and himself back out to the pool area before she got inside.

Speaking of getting inside, Susan did not notice her brother’s semen soaking the crotch of her swimsuit as she put it back on, thinking it was just pool water. She was in such a hurry to get back into the pool that she did not notice as the dangerous substance was pressed against her vulva by the tightness of her suit. She dove into the water of the pool and did not notice a little of his seed slip between her bare vaginal lips each time she kicked her strong legs as she swam from one end of the pool to the other in order to warm back up.

She would notice something in a few weeks, though, or a lack of something: her period.