Forum:About fairy box

so lets say i got no monsters on my field, a face-up fairy box and and a sakuretsu armor set. My opponent attacks my life points directly so fairy's box effect activates. However i call the coin wrong. Can i activate sakuretsu armor at this time or have i missed the timing?79.107.8.64 (talk) 09:16, August 23, 2011 (UTC)