So you pretty much use the phrase:
"if you could ___ right now, who/ what/ where/when/ etc____"
Some examples because that might be confusing :P
Person 1: "if you could [ride] right now, where [would you ride]?"
Person 2: the woods on a trail
If you could have any type of phone right now, what kind of phone would you get?
Person 3: the iPhone
If you could... etc
Any question (age appropriate of course!) doesnt just have to be with horses!
I will start!
If you could ride any horse right now, what kind of horse would you ride?