is this cake blue, or does it just appear that way in the photo?
i used to decorate professionally, and writing was always a pain for me, mainly because with my handwriting, i pretty much print and it's very idiosyncratic (could never do the standard script taught in schools) and the side of my hand always rests on a surface when i write. for decorating, i finally decided to just print, which works much better for me, which i do in either a stylized calligraphic square-shape script, or in a cute rounded print that's more like my personal handwriting (the letters are shaped with thicker rounded ends).
if writing on cakes is really your enemy, you may want to make friends with melted candy/chocolate coating. it will take a little practice, since it flows much faster than icing (when you finish piping, lift up your piping bag while sliding a finger from your "steadying" hand under it and over the tip to prevent drips), but here's what you do:
make up some paper piping cones (you could also use plastic disposables -- basically you want a piping bag that you can cut to use without a tip and then toss).
melt your candy coating (i like the microwave in a glass dish at 50% power for about 2 minutes, then stir to melt completely).
fill your cone half way, fold the top, and then cut your tip with a knife or scissor to the size you want (start small, as you can always go bigger).
the trick with coating is that you can pipe your message onto wax paper (on a plate or board) in either individual printed letters or fancy script with all the letters attached. chill in the fridge, and then slide an angled (offset) spatula under the letters or words, and then place on the cake. what's great about this is that it's no-fail -- you can make as many copies as you want, and you avoid spelling mistakes directly on the cake, etc. you can even attach the letters/words to the side of a freshly-iced cake (press slightly).