EDIT on the 24th July; Oh well, things didn't work out
, one player dropped out of this site altogether after only 3 days of posting, a"GM" male partner apparently had writer's block.
I'm just going to float this idea, and see what people think. Personally I want to be a player, not the GM of this.....
One of the ideas that I was thinking about;THE INVISIBLE MASTER
(based on this.... http://www.answers.com/topic/invisible-master and this ... http://en.wikipedia.org/wiki/Invisible_Master
A group of beautiful & sexy teenage high-school girls (16-18) is enslaved by a mysterious shadowy creature and turned into it's sexual playthings, but nobody else seems to be able to see anything wrong with what is happening to them.
The Invisible Master is a man-like shadowy figure, usually invisible to everyone except his targets. He/it mind-controls/changes the teenage girls to be his/it's sexual playthings, transforming them to look like a teenage guy's over-the-top wet-dream fantasy (bigger breasts, tighter waists, longer legs, pussy made hairless, etc...), and makes them constantly horny and wet to the extreme, and magically changes all their clothes to be very scanty & sexy clothing (all their underwear disappears, they can't even wear it anymore, and their shoes change to pumps with 5”-6” heels, and they can only wear the tiniest of skirts or a mere top/t-shirt). The Invisible Master has the power to fuck the girls even in public without anyone else being aware of what is happening, force the girls to wear almost nothing or go totally nude (yet everyone else will accept this as normal for those girls while still being aroused by it, taking advantage of them). The Invisible Master's power to control minds can cover whole towns, and it can change the shapes of things, shape reality (like changing it's victims' entire wardrobe, and play with them with an invisible dildo as they try to act normally in a shop). It can also split itself into multiple copies of itself to have sex with all of them at the same time (so that all the girls have to deal with all night sex at the same time).
The Invisible Master could come in and take-over during the middle of an all-girls sleep-over, getting all the girls at once and then take over the house - even the parents go along with it (they're mind-controlled to accept everything as being normal). The girls would be in for a big shock, but then have to deal with the erotic results, as the Invisible Master enjoys encouraging them to play with each other as well (making them too horny, and making it a rule that no girl can resist being sexually touched/played with by anyone else, and the rule that when greeting each other deep-tongue-kissing and groping always happens...kind of both to embarrass them when they do this in public as well, but also to increase the chances that things will go a lot further).