Looking at herself in the mirror, Jenna knew there was probably someone sexier than her out there, and she just couldn't have that.
"The reason I'm so sexy," she explained, "is because I can alter anyone in any way I want, and everyone but me thinks it had always been that way, while I know both how it really was and how, from my perspective, everyone else thinks it is. Others can also gain or lose this knowledge as I choose. I'm also immortal, unaging and untiring, and have complete control over time so that I can be sexier than anyone who ever was, or who is, or who will be."
Jenna blinked. Of course that's how she maintained her title as sexiest woman in the world. Nobody except her knew, of course, which had allowed her not only to be sexier than everyone else all the time but also to have lots of fun doing whatever she wanted to people without anyone thinking it at all strange.
Take their sex ed class. It was all boring stuff, use condoms, use birth control, blah, blah, blah. Nothing they hadn't heard before. So Jenna livened it up. Now it was all about having sex, different kinds of sex, different positions. She'd even made sure everyone had sex in a whole variety of different bodies, and made sure they kept their memories. She'd stretched the classes--and everyone's stamina--sometimes even to centuries at a time, so that everyone had run the full gamut of body types and sexual experiences.
They'd gone through every combination of short to tall, tight to loose pussy and ass, thin to cock-sucking lips, short to long tongue, flat-chested to hyper-busty, small penis to the proverbial hung like a horse, squat legs to can-can dancer legs. They'd investigated whether blondes really did have more fun, and whether it was best bald, with hair to the floor, or somewhere in between. Some preferred a flat butt, others a ghetto booty. BBWs were a hit with some and a turn-off for others; similarly different ethnicities produced different reactions. Everyone had sex with everyone else, in every form, in every number, from pairs through to a full class orgy. Even though Jenna turned the ones who weren't already bisexual back to their original orientations, they all knew what it was like to enjoy sex with and as either gender. All in all she felt it had been a much better use of the time than the regular curriculum would have been, as everyone in the class came out of it knowing exactly how to please their lover, even out of bed thanks to the days she had them spend in their preferred body and mental state from the other sex. Of course, they were a bit fuzzy on the details of how they came by all this knowledge, but put it to good use nonetheless.
She also used it to reward and punish. Her control over people extended to giving them multiple bodies to control at once, and she usually used this on herself to look in on many things at the same time. Nobody thought it strange, of course; they just thought she had identical siblings whenever she did it. In this way she was able to keep an eye on people whom she thought might deserve a reward or a punishment.
Take Sarah McMillan. Head cheerleader, but general all-around bitch. Or at least she had been head cheerleader, until Jenna decided to follow her around for a day, slowly sapping her attractiveness each time she demeaned someone. By the end of the day she was drab, flat-chested and generally quite unattractive. Her boyfriend made out worse, if possible, going from captain of the football team to scrawny wannabe jock with a two-inch dick.
On the other hand, take Patrick Carruthers and Melinda Best. Consummate nerds, not much to look at, but two of the genuinely nicest people Jenna knew. After she followed them around for a day, they were vastly improved in the one area where they were lacking. Patrick sported a 7'9" body packed with hard muscle and, as only he, Melinda and Jenna knew, a penis to rival almost any mammal's. He didn't like the idea of being physically dominant, though, so Melinda was of a height with him, and while she was equal to him in strength (in which they were above almost everyone else) her muscles enhanced her sexiness. Her hourglass figure, giving her a large but firm butt, a waist that seemed to be all abs, and watermelon-sized tits also helped, of course.
Despite constant pleas from the athletics department, though, they steadfastly refused to join any sports teams (or the cheerleading squad, even though Melinda had been guaranteed the captaincy) and planned to go into academia together, Patrick in microbiology, Melinda in pure mathematics. They even refused to be named prom king and queen, despite being the unanimous choice, on account of their feeling that they didn't deserve honours awarded on the basis of things they felt they hadn't done anything to earn. Instead they had persuaded everyone to crown Sarah and her boyfriend king and queen--the two had been quite different after Jenna's punishment. Jenna didn't regret the punishment, though--she knew that if they got their old bodies back they'd be as bad as ever.
She also used it to play pranks, which she occasionally allowed others to notice. Nothing truly harmful, and always reverted afterwards, of course. Altering a news anchor's body live on air. Changing the principal's sex multiple times during one of his (or her) boring assembly speeches. Putting people (and sometimes herself) inside TV shows or movies, in whatever role she chose. Stuff like that. It was always fun to observe the reactions when the anchorwoman's boobs burst her blouse (and the camera didn't immediately cut away, of course, because she wouldn't let it), or when the principal's voice changed pitch repeatedly, or when an episode's plot was drastically altered by the appearance of a benign demigod (namely, her) not bound to any sort of script. All changed back and forgotten by everyone but her, of course.
Of course, whatever she did, nobody could ever hope to be as sexy as her, no matter what body she gave herself. She exuded an aura, so that anyone who saw, heard or even smelled her (or any reproduction of her) immediately agreed that she was the epitome of sexiness, completely incomparable. Their usual likes and dislikes would decide who else they preferred, but they were all by far second best compared to Jenna. She'd even put it to the test: finding a hundred fans of heavily muscled, tall, busty women, she put herself in a small, scrawny, limp body and went to them with Melinda for comparative purposes. They all appreciated the other girl, of course, and lost none of their liking for women like her, but Jenna was foremost in their dreams ever after.
All in all, thought Jenna, life was good. She was the sexiest woman in the world (and the sluttiest--there weren't many adults who hadn't had sex with Jenna in some form), and, of course, would always be so. People, she felt, were better off than they had been before she'd begun using her abilities to try to make the world a better place. Sure, she'd punished people, but only when she felt it was the best course for improving general happiness.
Indeed, life--for everyone--was good.