So basically what it is if you haven't heard of it. It's like letters. You take an envelope wrote open when... You miss me. And inside the envelope you put something that ties in with that. I need more ideas. I've thought of things like.
Open when you miss me.
Open when you're sad.
Open when you need a laugh.
Open when you forget how much I love you.
But I need more. I'd appreciate the help. :)