Tips for toddler birthday cake

[Scaredycat3000]

I'm going to go and hire a dinosaur cake tin tomorrow. It says it takes a 5 egg mix. I am familiar with making and decorating grown up cakes with flat sides and (bought icing) sugarpaste, but not fun cakes. I have an aversion to Victoria sponge and would rather use sugar paste than butter icing.
Can anybody advise as to how to make sure the cake doesn't stick, a different recipe that might be a bit moister than Victoria sponge and what amounts I will need, any tips on applying the icing, etc.
Any tips/ideas would be great

Make a chocolate gooey fudgy cake???? Grease and flour the tin and it should come out easily enough. If you can line the bottom of it just for extra...

Icing's a doddle - if you can do it on a standard cake, you'll be fine with dino. Maybe roll it a little bit thinner, but it's not as hard as one might imagine. Honest.