Vince met Mandy at the carnival that was the official kickoff for the summer vacation. Now his success with girls was usually a long drawn out process. You see, despite his trim figure and good looks, he was a little on the shy side, but he hit it off with her the moment they met.

They spent the day together riding the rides and talking. Like him, she was seventeen and facing the last year of school. She attended a rather exclusive all-girls school which explained why he had never seen her before. It was on the the-laugh-in-dark ride that she allowed him to kiss her for the first time and it was the greatest kiss of his young life.

They wound up riding that ride a lot that afternoon. The operator must have been a fan of young lovers because he would pause the ride once inside which allowed the longer times of kissing and touching. At the end of the day, she informed him that if he wanted to keep seeing her, he had to meet her parents. She gave him her address and asked that he stop by around seven.

So around seven, Vince rode his motorcycle to Mandy's house to meet her parents who took a liking to him. He also met her sixteen-year-old sister, Kathy. Kathy managed a strangled hello before leaving the room. They apologized for her by saying that she was a little socially awkward. Mandy and Vince were invited to hang out in the basement providing he behaved himself. 

As with most homes built in the 1950's, this one featured a finished basement including a pool table. They shot a few games of pool and managed to steal a few kisses between shots. Vince didn't stay long and took the time to say goodbye to her folks before he left and that set the tone for the entire week.

It was on Saturday that he arrived and found her parents getting ready to leave. He was invited to stay as Kathy was home to keep an eye on them. They headed to the basement and started playing pool. The game lasted until they heard her mom say goodbye and the side door slam.

A second later they flew into each other's arms. Their lips mashed and tongues touched as they ground their young firm bodies against each other. They managed to make it to the couch and sit down while still kissing. 

One of Vince's hands gently squeezed and cupped her generous tits while the other stroked the length of her silky legs. Mandy then surprised him by taking a seat on his lap facing him; he now had access to both breasts and her firm backside that was covered by silky shorts. As he ran his hands over her tight butt he became aware of the heat from her pussy against his groin.

She stopped kissing him long enough to pull his t-shirt over his head. Mandy then planted soft kisses and licks on his bare flesh. She only stopped kissing and licking long enough to pull her t-shirt off. She ran her hands over her bra cups and then pressed it against Vince's naked chest.

His cock grew hard in its denim prison and based on the way she began to grind her groin against his she felt it. Soft moans escaped her nose as their tongues danced in each other's mouths.

"You need to lose these," she said, breaking their kiss.

"After you," he responded.

Mandy stood up and shimmied out of her silky shorts as Vince literally tore his jeans off. Mandy stared at his cock making a pup tent out of his briefs and smiled. She embraced him again and ground her silk-covered groin against his and his sensitive cock could feel her heat through her panties.

"What about your sister?" he asked.

"No worries. She's probably in her room wearing her headphones and reading. Now take off my bra," she whispered in his ear.

Soon her naked chest was against his as they commenced kissing again. The feeling of her erect nipples against his warm flesh was unbelievable. She then tugged him off the couch and they took a position in the shag carpet where he kissed and licked her erect nipples as his hand slid past the waistband of her cotton panties and into her hot and wet pussy.

He grabbed his jeans and extracted a string on condoms that he had begun to carry once he learned that she was not a virgin  He tore open one package and expertly placed it on his throbbing dick as Mandy slid out of her wet panties. There was some momentary jockeying for position until she parted her legs to indicate that she was ready.

Once again he marvelled at how hot, wet and tight she was as he pushed himself inside her. She gave a small whimper and moaned as he slid deeper into her and soon was buried up to his hilt. He then began the slow in-and-out movement in between kissing her lush breasts and lips.

It was a minute or so later that a movement on the steps leading upstairs caught his eye. He strained his eyes until they finally focused and couldn't believe what they saw. For there, seated on the third step from the top and barely visible in the shadows was her sister, Kathy. She had one hand down the front of her shorts and he could just detect the movement of her hand under them. He could also see that her other hand was on her right boob.

Kathy gently rolled and pinched her breasts as her other hand moved under her shorts. Kathy was intently watching him ball her sister and masturbating at the same time. This turned Vince on even more and he increased the speed of his ride which caused Mandy to moan a little louder.

As he dropped his head to lick Mandy's erect nipples again he locked eyes with Kathy's. She returned his stare and then continued masturbating with her eyes locked on his. Mandy's breathing increased and she crossed her silky legs across his naked back.

"Oh baby, I'm going to cum," she panted.

That admission caused him to increase his speed. A minute later her legs tightened across his back just as her internal muscles tightened on his cock. A sustained moan escaped her lips as her orgasm arrived and he quickly followed. He noted that Kathy was no longer on the stairs.

Vince got off her and took his place at her side and pulled her close. They held each other talking and gently kissing and Vince decided not to tell Mandy about Kathy watching. From that day on, whenever they had the opportunity to fuck, Kathy was on the stairs watching them.

Now, normally she wore sweatpants or shorts. However, one time Kathy wore a miniskirt with no panties and he was treated to brief glimpses of her pussy and her fingers slipping inside herself. This was a fantasy come true. Vince had his hard cock buried in Mandy and was treated to the sight of Kathy masturbating as she watched them.

It was on Thursday in the last week of June that Mandy announced that she was going out of town tomorrow. She would be gone for the weekend and that she wouldn't be back until Sunday. She promised to call him the moment she returned.

Friday arrived and as Vince drove by her house as he was headed out to hook up with some friends and surprised that there were lights on. He saw the slim silhouette pass by the shades and realised that Kathy must have remained behind. A wicked idea crossed his mind as he turned his motorcycle around and came to a stop at the side door.

He dismounted his Harley and rang the doorbell and waited. A moment later Kathy opened the door.

"Mandy's not home," she said softly.

"I know. I came to see you," he responded.

To be continued.