Quarter the chocolate candy lengthways and use the coffee whitener to fill an empty glass bottle with a screw or swing top, depending on your taste. Pour the hot coffee over it. Close the bottle, hold it with oven gloves and shake until everything has almost liquefied.
Let the bottle stand for a few hours until you can safely touch it with your bare hand. Then put the bottle in the refrigerator for a few hours. If you put the bottle in the fridge too hot, it will heat up.