A cool mum doesnt go around wearing sunglasses like a celebrity avoiding paparazzi (aka the school run). She doesnt worry about trends (because she knows what works for her). She listens without fixing and intervenes only when necessary (which is less often than you think). She also knows that most things pass (and that the rest can be handled with a cup of tea and a chat). You secretly know your mum is the coolest mum there is. So treat her on her birthday, or for a Mothers Day gift, to a Cool Mum 1/2 Pint Mug and let her know that, on balance, shes doing all right.
