our cubs jumped on top of our new male leader the other day... i did that 'oo, not sure how to react to this' pause, wondered if he was going to get off the floor and assert himself, mouthed 'wtf?' to the other (female) leader present, and then shouted like a banshee to get their attention.
if only i'd had a foam football 
he picked himself up off the floor in a faintly sheepish manner. the cubs were Very Good for about a minute and a half.
i wouldn't be a teacher for all the money in the world.
i don't think the cubs saw me mouthing the 'f' word - they had their heads down pummelling the new boy chap...
anyway, anyway, jolly ggod idea, whoeveritwas, op, just say to your ds 'that is totally outrageous darling - come with me - we will both make a FORMAL complaint AT ONCE! i will NOT have you humiliated like this in public. how DARE she beat you! let me call the other children's parents and get them to come with us!'
pound to a penny he blushes like a virgin as he knows it was a perfectly innocent 'oi, pay attention in my lesson, you little scrote' moment.