One weekend, my parents and another couple left for a four-day trip together, and the couple asked me to take care of their fourteen-year-old twins. I was glad to do it since they have a big house in Dunwoody with a private pool. I knew the twins, and I knew they wouldn’t be any trouble. What I didn’t know was that they had grown up during the year I was away at school.

Robert, or Robbie as he was called, was about six feet tall and weighed about 160 with a curly mop of blond hair that had been sun-lightened that summer. He was on the basketball team, so he worked out with weights and was really a sexy guy, what with his broad, tanned shoulders, narrow, flat stomach, and tight, rounded ass.

His sister was the exact opposite. Robin was only five feet two inches tall and probably didn’t weigh 90 pounds. She had freckles and she wore her red hair in braids with a pigtail on each side. With her pug nose and diminutive stature, she looked to be only ten years old except for her breasts. They were the size of half a grapefruit, and, as I later learned, were just firm.

On Saturday morning, I took the car to get some groceries, but I came back in a few minutes to pick up the list that I had forgotten. On the way back to the car, I looked out at the pool deck because that was where the kids were when I left. I couldn’t believe what I saw!

Robbie was lying on the patio table with a towel over his eyes and was spread-eagled with his swim trunks pulled down to his ankles. His cock was sticking straight up his stomach as Robin rubbed her hand up and down his thighs. Robin was topless, and her tits really did resemble grapefruit halves. They were completely rounded and had no sag whatsoever, and her nipples were a bright pink rose on the white flesh of her breasts.

She picked up the suntan oil and poured some on Robbie’s chest and began to massage it up and down toward his cock. She poured some oil on her tits and put Robbie’s hand on her breast and, with her hand behind his, pressed his hand into her tender breasts.

He began to rub it in as a bead of cum appeared on the head of his prick. Then Robin leaned over and, with the nipples of her breast, stroked his cock from head to balls, letting him feel her hardness on his sensitive skin. He was still blindfolded by the towel, and I moved closer to the screen door so I could hear them but not be seen.

Robin was telling him to imagine that she was Cathy (me) and that I was going to beat him off. She described my body in detail (although she had never seen me nude) quite accurately and took Robbie’s hands for a tour of her own body. I opened my jeans and slipped my hand down the front of my panties to my clit and pussy lips. I began to stroke my way to the inevitable climax while I watched Robin masturbate every part of Robbie’s body except his cock.

She poured some more oil, this time directly on his cock, and Robbie arched up from the table. She grasped his cock and began to rub one hand up and down his seven-inch shaft while the palm of the other hand rubbed on the head of his cock. It was more than either Robbie or I could handle, and we came at about the same time. He was spurting all over his chest and stomach and I had to hold on to the curtain in order to stand up.

Robin rubbed her tits across his chest and stomach, drenching her nipples in his cum, and then massaged it into her flesh.

I recovered my composure before Robbie and was off to the supermarket, although with the germ of a plan in my mind. On the way home, I worked out my plan, and I stopped by Fredrick’s of Hollywood and purchased a wet-look black string bikini.

When I returned, both kids were in their swim gear, although it really didn’t hide much, and I said hello and explained that I would be out after I put the groceries away.

I went to my room and stripped in front of the full-length mirror. I pulled the rubber band from my long, blond ponytail and let my hair hang down straight. I used a brush to get the kinks out, and the feel of the bristles against my sensitive nipples made them erect and hard.

I put the new bikini around my waist and adjusted the bottom so that most of my ass was showing, and then put the bra on. It was only a strap, which was about three inches wide, so it couldn’t hold all of my breasts. About two inches of the tender, white underside of my tit was exposed along with about four inches of the tanned top of my breast. I put on high-heeled sandals and practiced prancing and strutting.