How do you add a spoiler?

[Mayor_Sarah]

I seriously can't figure this out. How do you add a spoiler to your post?

 

[Aradai]

here you go!

[spoiler]wow lookie at all of this stuff[/spoiler]

if you want to name it:

[spoiler=name!]more stuff![/spoiler]

there's also the thin one

[spoiler=" "]i once told a woman i was kevin costner[/spoiler]