Naked and eager, Billy stood in front of the full-length mirror his older sister had put on the back of the closet door. He grasped his swollen scrotum and turned sideways.

He smiled. It was, he had to admit, really impressive. He lowered his cellphone, took his hand away from his balls and took a picture of his fully engorged and rigidly curved penis. It arched up higher than his navel and its tightly stretched skin was laced with blood veins. The helmet-capped head was heavily ridged and spear shaped, a split tool of pleasurable penetration, and his globular scrotum was obviously filled and ready for action. His urethra a thick keel to his big cock.

He shook it from side to side and took another shot as it continued to swell, the head turning purple.

Billy knew, from talks with both his father and his fraternal grandfather that impressive endowment was a family trait, and that he should not be surprised if, when he matured, his genitals were somewhat out-sized. He smiled at the word his father had chosen, outsized. He smacked his erection and watched it bounce and jerk. Just the right size, he thought, the right size to produce screams of pleasure. He was sure girls would love it.

Billy was a 15-year-old who masturbated to ejaculation at least twice a day, sometimes unconsciously in his sleep. His mother had noticed the stains more than a year before and said she understood that it was a sign of his maturing but that he should try not to soil his sheets. So he jerked off before he slept most evenings, gritting his teeth to keep from gasping in release.

And he generally exercised his male muscle after school with the help of computer porn and now that summer was here, he sometimes managed three pleasurable sessions with his thick cock, including one in the shower. He had undergone a growth spurt during the last six months that had added to his height, the size of his feet and the girth and length of his penis. Even when it was barely excited, it was big, both thick and long.

Now his big sister was coming home from college, and he was being exiled to the basement and a pull-out bed. And he had a surprise for her, a big surprise. She had sent him a picture that he treasured and often used when he jerked his big horn.

He sat at his computer, copied the cock pictures to his secret file and looked at his penis on the screen. He tried to think of it as somebody's else's, like the ones on the Tumblr site, and had to admit it was impressive, almost as good as any he had seen on the Internet, and he had looked at many. It curved up wonderfully and was a really good color, pale and blood-vessel streaked with a reddish crown. He eased it out and caressed it gently, eager to see his sister and get her into his bed.

He was still getting his stuff together when his sister arrived in a yellow Z-car along with a long-legged blonde she introduced as Taylor, her roommate at college. Billy's cock lurched. His sister was pretty, but this girl was beautiful. She had long, pale blonde hair, a lovely face with full lips and a patrician nose, a pair of bobbling jugs that were very impressive and long, long legs. She smiled at the boy and licked her lips as she noticed the movement in his groin. He praised her little car, and she smiled and said it was fun to drive.

Taylor Griggin had discovered of joys of sex at college. She had done it with a few boys in high school, just meaningless hook-ups after her brother and three of his friends had introduced her to the pleasures of her body on rainy afternoon when she was barely fourteen. It had taken several hours and all her tight orifices. She and her brother were secret lovers until he quit school and joined the Marines. By then she was sixteen and a constantly horny high school junior.

Now Taylor was becoming selective, but she was still exploring and willing to try almost anything for pleasure. In the second semester she had enjoyed twenty-three different lovers, often three a week and sometimes two at once, but dallied and slept with only two of them. She lived with one young man, a grad-student, for more than a month until his financé caught them copulating one afternoon when he should have been in the library. He loved to do it standing with the girl's back on the wall. The other one was a jock with a big prick, and she fucked him for a week before she tired of his abrupt pull-outs and his rough stuff.

Now here was this kid grinning at her, and she could tell he was in the process of getting a hard-on. She and the boy's very sexually-active sister, who had had as much sex as she had but with fewer partners, went up to their bedroom.

"Have you fucked your brother," she asked. She and the boy's sister had, on occasion; gratified each other when they were sick of men for one reason or another. Good old 69 was their favorite position.

"That nerd," his sister said, "of course not. He's a toad. I'll find you some boys; don't you worry. Let's get some sun and work on our tans. We'll being going down to the beach next week."

Both girls slipped into bikinis they had worn the year before, suits that had been exciting then and were nearly indecent now. Taylor managed to tie her miniscule bottom at her sloping hips and was glad she had shaved her pussy recently after one of her eager lovers complained about swallowing hair.

Billy was mowing the back lawn when his sister and her friend came out with beach towels over their shoulders. His pretty sister was wearing a pink one with her breasts overflowing the top, and the other girl had a tiny two-piece suit that was more exciting. He smiled at her and kept mowing, hoping his swelling cock wasn't obvious.

Both girls ignored him and spread their towels, lay back and took off their tops. Billy tried not to watch them as they oiled each other with tanning lotion and then rolled over to lie on their bellies. He finished the last corner and hurried to the garage, pulled down his jeans and pumped out his semen in a dark corner, biting his lip to keep from crying out as thick ribbons arched out and slid down the wall. Gripped with both hands, his big cock still stood out a good four inches and lurched as he painfully ejaculated.

The boy waited until he could breathe normally and then went back out and trimmed around the garden, doing is best not to look at the pair of nearly naked females. He was almost finished when his sister called, sat up with her arm across her deeply cleaved chest and asked him to bring them some bottled water from the refrigerator. He nodded. And ran. His sister giggled.