to hate mothers who go on and on about how they think their children are marvellous

[Klingyston]

Particularly one at school who does this all the time and in doing so puts my daughter down eg says hers is best at English in the class so by default better than mine. Really groom

rollmops sounds a very unpleasant kind of person, an arrogant reply.

There is an expression

Hungry children talk about food.