I'm in the middle of making my sister's wedding cake (for tomorrow!) and I've iced the three tiers, however, unfortunately there are cracks all around the edge where the top meets the sides. This hasn't happened before (typical it does when it's such an important cake). I've tried 'buffing' with my fingers and palm but they're still really noticeable. I've also tried a little warm water which also doesn't work.
How can I get the icing to smooth out?
Two tiers look 'ok' but the middle tier is terrible. HEEEELLLPPP