What do the two of you talk about?
Probably boys and love and all that girly stuff like fashion (sounds lame but you've got to admit it's fun!), and maybe talk about people/human nature in general haha. Just really personal stuff without being too nosy. I don't really want to talk about typical 'fan' stuff.

What are in the two cups the two of you have?
Most likely alcohol.

What item do you ask her to sign?
Probably the back of my phone or my shoe.

How do you exchange goodbyes?
Definitely a picture! And then a big hug and two cheek-kisses. Standard friendly goodbye