The youngest classes were quite hard - I had to think on my feet much more than usual. Few children liked to sit, and often went off on personal tangents, with little concept of the 'group' nature of the activity.
The teachers were really helpful though and I found that, if I stayed calm and bent with the wind, it was fine. For example, I gave up immediately on them doing individual drawings: instead I tore off flipchart sheets and, those that wanted to, all mucked in together. One little boy got very focussed when I got him to take turns with me, colouring alternate stripes on a snake.
I'm so glad I went for it and didn't let nervousness put me off. I was pretty exhausted when I got home, but felt I had connected with the children. The teachers all appeared genuinely pleased with how it went, so I reckon I did ok.