Mary Smith is sixteen-years-old. Her step-brother, Bob Eiger, is eighteen. Their parents are Bill and Jenny Eiger. Bill is divorced and Jenny lost her husband in combat. Mary chose to keep her father’s surname and not be adopted by her step-dad when her mother married Bill when Mary was twelve.

Before Mary’s Sweet Sixteen birthday party, Bob asked his step-mom if she had a picture of her husband that he could put in a locket. She gave him one that just the head would fit perfectly.

Bob bought a locket and chain, then had the words “I’m always with you” engraved on the back. He inserted the picture and on her birthday, had her close her eyes while he fastened the chain around her neck. When she opened her eyes and saw the locket, she was surprised. When she opened it, she burst into tears. Bob hugged her and told her to read the back.

When she did, she threw her arms around his neck, kissed his cheek, and said, “Thank you. That’s the best present I’ve had in a long time.”

From that day forward, Mary had a crush on her step-brother. Now, at age sixteen and a half, with hormones raging through her body, she was confused. She dated a few guys, but all they wanted was for her to get them off. She thought Bob was considerate and would never do something like that to her.

Though he wouldn’t admit it to anyone, Bob had a crush on Mary as well. He dated a lot of girls, had sex with many, and never left one unsatisfied. As far as he was concerned, none of the girls he dated could compare to his step-sister.

One day, Mary went to her mother and asked if they could sit down and talk privately. Jenny suggested that they go to Mary’s room for privacy. When they entered Mary’s room, Jenny closed the door and locked it.

“What’s bothering you, Mary?” Jenny inquired.

“Mom, I know it’s hormones, but I can’t get Bob off my mind,” she replied.

“Mary, it’s more than hormones. It’s also the crush you’ve had on him since he gave you that locket,” Jenny stated.

“How did you know I had a crush on Bob?”

“Honey, it was easy to see. You’ve followed him around like a puppy ever since then.”

“So what should I do, Mom?”

“Answer me truthfully. Do you think of having sex with Bob when your fingers are in your cunt?”

“Mom, I never thought you’d use that type of language!” Mary exclaimed.

“Answer my question.”

“Yes, I think about sex with Bob when I masturbate, Mom.”

“Do you actually want him to fuck you?”

“Yes, Mom, I do. I want Bob to be my first and take my cherry.”

“Then you’re going to have to seduce him. Let’s go shopping tomorrow to get you the right clothes for that.”

That same evening, Bob conversed with his dad while Jenny and Mary were preparing dinner.

“Dad, I have a problem,” Bob admitted.

“What up, son?” Bill asked.

“Dad, it doesn’t matter who I date. I’m always comparing them to Mary.”

“Bob, Jenny and I have noticed the crush you’ve had on her since you gave her that locket.”

“So what should I do? Eventually, I want to get married and I don’t want to be comparing my wife to Mary.”

“Bob, be straight with me. Do you jack off thinking about Mary?”

“Yeah, Dad, I visualize her being naked as I stroke my cock.”

“Have you thought about asking her out on a date?”

“I’m not going on a date with my kid sister.”

“She’s your step-sister, not your sister, Bob.”

“It doesn’t matter, Dad. I’d be the laughingstock to my friends.”

“Well then, you’ll just have to deal with it.”

That night, while lying in bed, Bill and Jenny discussed the kid’s issues.

“The two of them sound like we did at their ages,” Bill remarked.

“Yes, they sure do.” Jenny affirmed.

“So, how do we get them together?” asked Bill.

“Leave it to me, Bill. Mary is going to seduce Bob, and when he’s ready, we’re going away for a long weekend.”

The following day, Jenny took Mary shopping. During the drive to the mall, Jenny told Mary that she needed to select clothes that were sexy and accentuated her figure. When they entered the first clothing store, Mary chose three modest bikinis. Jenny nixed them in favor of three string bikinis that would barely cover Mary’s nipples and her slit.

“But Mom, they show everything but my nipples and pussy, even my ass is exposed,” Mary argued.

“That’s the idea, Honey. Get him drooling over you.” Jenny responded.

Jenny then selected three thin blouses that fit tight over Mary’s high-sitting 34C-cup tits.

“When you wear these, don’t wear a bra,” Jenny instructed.

“Mom, they’ll see my nipples poking thru the fabric.”

“Exactly!” Jenny replied.

Jenny paid for the purchases, then led Mary to the far end of the mall where Victoria’s Secret was located.

“What are we going in here for?” asked Mary.

“You need some sexy underwear and nightwear,” Jenny replied.

Jenny picked out seven bra and pantie sets, including one with a split crotch and one with nipple cutouts. She also selected two teddy sets, one black, and the other red.

“Mom, I can’t wear any of those.”

“Mary, the idea is to have Bob remove them.”

Jenny paid for the purchase, and they left the store.

When they got to the car, Jenny said, “Let’s do lunch.”

They went to Jenny’s favorite lunch place and, while they ate, gave Mary instructions.

“Now, you can’t be too obvious, Mary. Do things like wear a string bikini and lay on a lounge in the backyard while Bob is mowing the lawn. He also likes to study at the table out back, so that’s also a good time to catch some sun in a string bikini. Of course, any time you’re in the pool, you should be wearing one. On weekends, you should come to breakfast wearing one of your teddies with nothing underneath,” Jenny instructed.

“Mom, both men will see everything I’ve got!” whined Mary.

“Yes, they will, but Bill already has me. Would you be more comfortable if I came to breakfast dressed the same way?” Jenny asked.

“I’d be less nervous, I guess,” Mary stated.

“Fine, we’ll both go to breakfast wearing teddies with nothing underneath."

When they got home, Mary went to her room to put her things away. As she did, she decided to see what a string bikini felt like. She put one on, then went to the backyard and lay in a lounge to catch some sun.

Mary thought, “I feel so liberated having so little covering me.”

Jenny hadn’t seen Mary go out, and when she opened the back door, she was amazed at the sexy teen lying there.

“You look great, Mary. How do you feel?” Jenny asked.

“Like a new woman,” Mary replied.

“I’m sure Bob will like the new you.”

Jenny went back inside. Mary was still lying in the backyard when Bob came home. When he opened the back door to go to the table and study, he saw his step-sister wearing next to nothing on the lounge chair. His cock was instantly hard as a rock.

He held his book in front of him as he closed the door and said, “Hi, sis.”

“Hi, Bob. Do you like my new bathing suit?” Mary asked.

“Ye... Yeah, it looks great on you.” he stuttered as he walked to the table and sat with his back to her.

Mary got up and went inside, and started laughing uncontrollably. Jenny came to her daughter to find out what was so funny.

Mary controlled her laughter enough to say, “Bob got a hard-on when he saw me and covered it with his book.”

Jennie laughed with Mary, then said, “Wear your suit until you go to bed. I want to see how he handles being around you and the rest of the family.”

“Okay, Mom. This is getting to be a lot of fun.”

“You’ll probably get Bill turned on too,” Jennie stated.

When Bill came home, he went to the kitchen to get a beer from the refrigerator. Jenny and Mary were preparing supper when Bill came in.

Mary turned to him and asked, “How was your day?”

Bill looked up and saw her in her string bikini and said, “Holy Shit! Are you really my step-daughter?”

Jenny giggled and said, “See what a little re-modeling will do?” then they saw his hard-on as he stood up.

“I never imagined a body like that under those oversized t-shirts and hoodies,” Bill stated.

“So, you were mentally undressing my daughter, Bill?” Jenny teased.

Bob came in from studying, carrying his book in front of his crotch.

As Bob passed the kitchen, Bill said, “No sense trying to hide that hard-on, Bob. The women already know you have one like mine.”

Bob blushed red, then ran to his room. When he came out to eat dinner, he wore loose board shorts. The bulge from his hard-on was still visible. When he sat next to Mary, she played footsie with him and had one hand on his thigh. He was too embarrassed to say anything to the adults at the table. He sat there, occasionally squirming on his chair.

When dinner was done, Bill and Bob went into the den. Jenny and Mary cleaned up.

Mary told Jenny, “I was playing footsie with Bob and my hand on his thigh during the meal.”

“So that’s why he was squirming in his chair,” Jenny laughed.

When they finished cleaning the kitchen, Jenny turned to Mary and said, “You’ve really come out of your shell since you put that string bikini on. Aren’t you glad I insisted on them?”

“Mom, I told you outside that I felt like a new woman.”

“You sure are acting like a different person. Yesterday, you wouldn’t have been as forward as you were tonight.”

While the men were waiting for the women to join them, their hard-ons had subsided. When Jenny and Mary entered the room, they were immediately hard again. Bill was seated in his recliner, and Bob sat on the couch. Jenny took her usual seat, and Mary sat on the couch with Bob. Bill turned on a movie he thought everyone would enjoy and turned the lights down low.

About halfway through the movie, Mary laid down with her head in Bob’s lap. She waited a few minutes before taking his hand and placing it on a tit, holding it there with her hand over his. Bill and Jenny saw what Mary did and wondered how Bob would react.

To their surprise, when Mary removed hers, Bob didn’t remove his hand. Instead, he pushed the little triangle covering her nipple aside, then pinched and pulled on her nipple. Mary moaned softly when he did that. He massaged that tit before he uncovered her other nipple, treated it the same as the first, and then massaged it. The pussy cover of Mary’s bikini was now soaked with her juices. She got up, took his hand, and pulled him to her room.

When she closed the door, Mary stripped. Bob just stood there and watched.

“Get out of those damned clothes and fuck me, Bob!” she yelled.

“You’re my sister, Mary, I can’t.”

“I’m your step-sister, dammit, not your sister. You’ve got me so damned horny. Do you leave your dates hanging like this?”

Mary unbuttoned his board shorts, and they fell to the floor. He had no underwear on, and his hard cock stood proudly.

Mary pushed him back onto her bed, got on the bed, then mounted his rigid cock. She played with Bob’s balls as she moved up and down his cock. Mary was surprised at his staying power, expecting him to cum quickly.

Bill and Jenny expected to hear the headboard on Mary’s bed banging on the wall. When five minutes passed without a sound, they were confused.

Suddenly, Bob couldn’t take anymore and pulled her to his chest and rolled them over. He started pounding Mary’s cunt. When Bill and Jenny heard the headboard banging, they knew everything would be okay.

“Fuck me, Bob. Fuck me and make me yours,” Mary yelled.

Bob balanced his weight on one hand and twisted her nipples as he fucked her.

“Yes, Bob. Twist them, pull on them, pinch them, they're yours to do what you want!” she screamed.

“Aieee,” she screamed as an orgasm suddenly took her to heaven.

Bob continued to pound her through her orgasm, slowly building to his own.

“YES, YES,” she screamed as a second orgasm built on the first.

Bob again continued pounding into Mary’s cunt through her orgasm until he finally felt his cum rising.

He stabbed his cock deep in her cunt and, as he came, yelled, “I’m cumming in your cunt”

“Yes, Bob, cum in my cunt,” Mary screamed as she felt his cock expand with each shot of cum.

When he finished cumming, Bob rolled off of Mary, and they cuddled while they recovered. After a while, Bob leaned over Mary and kissed her. It was no brotherly kiss but the kiss of a lover.

When they broke the kiss, Bob said, “Thank you for forcing the issue. I was hung up on the sister concept.”

They cuddled a little longer, then walked naked to the bathroom and showered together. When they finished showering, they went back to Mary’s room to dress before facing their parents. Bob put his board shorts back on. Mary put on a red teddy.

When the kids entered the kitchen, Bill and Jenny sat there smiling.

“Why are you smiling? I just fucked my step-sister,” Bob asked.

“We know. You two were pretty loud,” Jenny chuckled.

“What’s so funny, Mom,” Mary asked.

“Bill and I are step-siblings. We set you both up to awaken you to your feelings for each other. Neither of us thought it would happen on the first day. That string bikini really brought you out of your shell, Mary. When you put your head on Bob’s lap, I thought that our plan worked, and when you pulled Bob to your room, I knew it had,” Jenny explained.

They all came together for a group hug then Mary and Bob returned to her room. The following day, Bob moved in there permanently.

Six months later, Bob and Mary went to get a marriage license. It was easy because she insisted on keeping her father’s surname and not taking Bill’s.

A week later they were married in a civil ceremony with their parents as witnesses.

Two years passed before they were blessed with a baby boy. They named him Stanley, to honor Mary’s father.