ENF/ENM Tickle Fics

Have you ever watched someone being tickled and thought, "this looks agonizing, but what if they were naked and everyone could see them? That would make it truly unbearable..." Well, it's about to happen to you.
How did you get in this situation?
Revenge?
Blackmail?
A bet or dare?
Punishment?
Cruel bullies who love seeing you squirm?

Let's not get ahead of ourselves, firstly, who are you?