It used to be:
A school to teach teenagers how to pleasure society. That's what the School of Water Business is. Of course, the pleasure would be performed within water businesses. What's a water business? Just think of it like a place you'd go to to get a massage, and any part of the body you wish... And your massuse could use any part of their body they wished... And they just happened to be girls... Well, you get the idea. As you might have guessed, this manga is not for little kids.

I have to admit this description is way more appealing, and flows better than the one I've replaced it with, but I couldn't leave it because it was inaccurate. The school doesn't just teach girls, and the fuuzoku (closest to what this describes) don't perform that kind of massage... or, well, if they do, I've never heard of it, usually you just see them peforming "a thousand strokes" on wooden cylinders.

So yeah... if anyone has any suggestions on improving this I'd love to hear them. I tried to phrase the idea of this manga as accurately as I could, and so replaced the description with that in mind.