Smellbow now dear, don't disparage yourself - there's no such thing as a stupid question. Repeat after me, please? Well done.
In the simplest terms, 'mansplaining' is exactly that - a gentleman explaining a concept to a lady. Why is it 'a thing', as young people say? Well, it all boils down to what I was saying earlier. Men have logical brains, and women have emotional brains. Your emotional brains mean that you are superbly equipped to perform many jobs. You can tell what men are thinking, almost before they know it themselves. You know instinctively how to calm us down after a stressful day at work. And multitasking? You only have to watch Mrs Barry cleaning and sorting laundry while getting a full Sunday roast underway to appreciate the formidable female brain running at full power.
However, nobody is perfect, and unfortunately in order to benefit from your female brains, you have had to sacrifice certain skills, such as maths, politics, science, technology, engineering, history, geography, medicine, finance, business, sport and literature, to name a few. That's where mansplaining comes in. Our logical brains enable us to grasp these trickier concepts, and break them down into easily digestible chunks for you. You're welcome!