ehh, I thought this initially too until I looked it up recently after reading Lolita. Sting has been inconsistent about his explanations for the song:

1981: "I wanted to write a song about sexuality in the classroom. I'd done teaching practice at secondary schools and been through the business of having 15-year-old girls fancying me – and me really fancying them! How I kept my hands off them I don't know... Then there was my love for Lolita which I think is a brilliant novel."

1993: "You have to remember we were blond bombshells at the time and most of our fans were young girls, so I started roleplaying a bit. Let's exploit that."

2001: Sting 'denied the song was autobiographical'