There's nothing as annoying as making a nice hot cup of tea or coffee and then putting in your milk or cream and making all luke-warm. To avoid this, put your cold creamer in before you pour the hot liquid. Because liquids transmit heat more efficiently than air, your creamer will absorb more energy from the hot liquid than will the surrounding cold air, meaning that the creamer will heat relatively quickly and completely before the hot beverage cools. Plus, you'll gain a lot just by starting your creamer at room temperature, rather than at fridge temperature.