[Guest post by Grumbles]
1 - Get a nice big sheet of paper out.
2 - Tell mum repeatedly what you'd like drawn. I found, in this instance, that saying "Cats, Mummy! Let's draw cats!" over and over again finally wore her down.
3 - Jump up and down in excitement while aforementioned cats are being drawn.
4 - Offer to help Mum with paints by squeezing the paint onto the bathroom floor. This step isn't really necessary, but I find it's always good for a laugh.
5 - Get stuck in! You can paint on the actual paper if you like, but I also find painting the table, chairs (usually prompts Mum to bellow "No, Grumbles, not the chair - it'll staaaaaaain!", and then make a mad dash for a cloth to wipe it up. Totally good fun!), more of the table, and my new dress really gets the creative juices flowing. Oh, and a word from the wise: try not to lose interest after only a few minutes. That can really make for a grumpy Mummy, and she might withold your afternoon banana or even worse - not let you get the glitter out to sprinkle over everything!