The Rules for this are rather similar to I'm Thinking of. Someone posts a Your First _______ was...? And then the next person answers, and then asks another Your First question. Example:
User1: What was your first car?
User2: A Dodge Neon, who was your first friend?
User3: Isaac Johnson, how was your first....
Quite simple really.
All credit for the premise goes to Xer07.