That's my battle-cry anytime I see frosted cake--even if it's someone else's birthday. Since the frosting is the best part of the whole confection, I've always made a grab for the frosted roses.
What's funny is that I nearly always get away with it.
Usually because very few people have a sweet tooth like mine and the massive sugar rush would put them into a coma. I also think it's because I provide some additional entertainment for the get-together: A grown man throwing a hissy-fit over frosted roses.
I've seen cakes like this (okay, drooled over them) and wondered what they'd taste like. Since my wife knows about my frosting fetish she bought me to this baked beauty for my recent birthday.
Of course I carved myself a big hunk (okay, and a smaller second piece) right away. The frosting was actually a light, non-dairy cream; tasting like sweetened Cool-Whip. The bakery folks told my wife that these cakes are often made with lighter cream so the roses and other frosted artwork can stand-up better. That such large frosted decorations would be too dense to hold its own weight using the super-sweet butter&sugar frosting.
So I didn't go into a coma. Not yet anyway. The folks at the bakery didn't say the never make a cake like this out of butter&sugar frosting...