The condition was incredibly rare, afflicting very very few, and even then, it seemed to only manifest in those who had begun puberty late, with rare few exceptions. Super-puberty was a second puberty, usually a few years later than the first, where a powerful hormone cocktail begins to swim in the sufferer's veins, enhancing their secondary characteristics to incredibly exaggerated levels, along with giving a powerful libido.
While eventually the changes would settle down, much as in normal puberty, the bodily changes were very much permanent. There are only a handful of super-puberty suffers worldwide, but our story today follows them. Perhaps they are a few years past it, and we catch up with them living their life with such an exaggeratedly sexualised body. Perhaps they are only just about to discover their rare condition and its attendant difficulties.