Smash the cake is one of the funniest experiences you can have as a photographer.
You'll need a pretty cake (professional look better), some subtle decoration and a gorgeous one year old eager to explore. Photographer with sense of humor is a must.
To be honest I didn't sleep well for a few days prior to my first Smash The Cake session. When you expect a carnage you are not quite sure how the situation is going to collaborate with your professional perfectionism to photograph same pose over and over till you get the perfect shot. In cake cases you'll need to be pretty quick.
From personal experience I've learned: