Is it standard practice to only "dirty ice" a cake before putting on fondant? I thought you could put on a regular layer of icing and still put fondant over it. Sometimes on the second day my fondant seems to begin drooping. Is it because it is shifting over the icing layer? Is there a way to avoid this? Most people don't eat the fondant so I like to have a layer of icing there, otherwise all you get is cake once you peel off the fondant. Does this make sense?

i always do a crumbcoat (dirty ice) then a normal full coat of buttercream/ganache which ever im using . I let it set up nice and firm for maybe an hour, before i put the fondant on, The trick really is the smoother and crisper you get your icing, the easier your fondant will smooth, But also, taking care not to 'smoosh' the icing under neath the fondant! Also, you dont want your fondant so thick that its too heavy for the cake to handle, and not so thin thats it going to tear . . If that makes any sense lol! Its not impossible to do, but sometimes it takes a little practise if all your used to is a crumb coat