So you say what a perfect match would be with the character/person above you.
So, if Cassie posted before me (above me) I'd say, Cassie and Adam if I thought they were a 'Perfect Match'
But you don't always need to use other characters - if you want, you could say something like Cassie and marshmallows, or chocolate, or whatever you think she'd like.
I start, but nobody above me so..