If I am given a topic “That incident became my little secret” for an essay, how ‘little’ must the secret be?

Make something up. It will be a lot easier to “reveal” your little secret if it’s not something true about you. This can be OUR little secret.

It can be a “big” little secret, or as little as you want it to be. The teacher/professor is leaving that open on your end, but personally I agree with the first person that wrote on that. Rather than actually sharing your stuff with the teacher, make something up. I did it several times in college, they never know and it doesn’t matter. They’re not grading you on your story….so make it up. Humor tends to get the professors attention more, so try to throw in some irony and stuff to get them interested in your story.