You simply ask the person below you, which of the two 'things' (places, games, items, weapons, etc.) they would choose from. The person below you answers, and asks a question of their own, and then so on.
Would you rather eat; A burrito or a Taco?
I would rather eat a burrito.
Would you live in either; Skyrim or Minecraft?
I would like to live in Skyrim-
-And So on.-
Which category of weapon do you like best; Ranged or "Physical Combat"
Which mystical creature do you like better?; Dragon or Fairy?