[she lets two of them climb on her a bit--they're not human and she's getting used to that part, but kids are still kids regardless. when they start threatening to over-balance her she scoops them into her arms one at a time and sets them back on the ground. it's a wobbly and ungraceful maneuver, but she manages it without toppling over!]

I can't say I've had experience with these children before, but usually you just need to be firm with them. If you don't want them doing something you say "no" very sternly.